fix: change db7 to 5byte frame header from 8byte header

feat: adds 5a diagnostic script to parse raw binary

CLAUDE.md

@@ -163,6 +163,83 @@ record — 5A remains the sole source for those fields and they are set uncondit
 `stop_after_metadata=True` (default) stops the 5A loop as soon as `b"Project:"` appears,
 then sends the termination frame.
 
+### SUB 5A — STRT record layout and rectime_seconds (CORRECTED 2026-04-14)
+
+The STRT record is 21 bytes embedded at the start of A5[0] data.  Offsets relative to
+the `b'STRT'` magic bytes:
+
+```
++0..3   b'STRT'   magic
++4..5   flags     0xFF 0xFE (single-shot) or 0xFF 0xFD (continuous)
++6..9   next_key4  ← key of the NEXT stored event (NOT the current event) ← confirmed 2026-04-14
++10..13 prev_key4  ← key of the PREVIOUS stored event                     ← confirmed 2026-04-14
++14..15 UNKNOWN   (values seen: 0xDA63=55907, 0xF38F=62351, 0x5685=22149) — NOT total_samples
++16..17 UNKNOWN   (values seen: 0x0122=290, 0x011A=282, 0x00FA=250)       — NOT pretrig_samples
++18     uint8     record-MODE byte — NOT rectime in seconds
++19..20 0x00 0x00
+```
+
+**CONFIRMED field values (2026-04-14) from 3 desk-thump events, firmware S338.17:**
+
+| Field | What it is | Confirmed |
+|---|---|---|
+| +4..5 | 0xFFFE single-shot / 0xFFFD continuous | ✅ |
+| +6..9 | next_event_key (NOT current) | ✅ 3 events |
+| +10..13 | prev_event_key | ✅ 3 events |
+| +18 | mode byte: 0x46 ('F') = single-shot, 0x0E = continuous | ✅ |
+
+**CONFIRMED (2026-04-14) — total_samples and pretrig_samples are NOT stored in the STRT record.**
+The prior documented offsets (+14..15 for total_samples, +16..17 for pretrig_samples) were
+WRONG — confirmed by cross-checking STRT-derived rectime against compliance record_time
+(4-14-26): all 4 events give STRT-derived rectime of 21–61 s vs actual 3.0 s (ratio 7–20×).
+Extending the STRT dump to 32 bytes confirmed that bytes 21+ are the start of the raw ADC
+waveform samples, not more STRT fields.  Blastware itself derives total_samples and
+pretrig_samples from the compliance config — exactly what our fallback does.
+
+**The compliance-config fallback IS the correct permanent solution, not a workaround.**
+`_decode_a5_waveform` uses:
+  - `pretrig_samples = round(0.25 × sample_rate)` (compliance monitoring standard)
+  - `total_samples   = pretrig_samples + round(record_time × sample_rate)`
+
+**CONFIRMED (2026-04-14) — waveform starts at strt_pos + 21 (no preamble).**
+The original `sp + 27` skip (STRT 21B + null-pad 2B + 0xFF-sentinel 4B) was WRONG.
+The 6-byte "preamble" in the 4-2-26 blast capture (`00 00 ff ff ff ff`) was actually the
+first ~0.75 sample-sets of quiet pre-trigger ADC data misread as padding.  Desk-thump
+events show different bytes at positions 21-26 (e.g. `00 10 02 00 ff fc`) — they are real
+ADC readings, not a fixed preamble.  The `sp + 27` skip discarded 6 bytes of real waveform
+data and misaligned the channel decode for all subsequent frames.  Fixed: `wave = w[sp+21:]`.
+
+The +6..9 next_key and +10..13 prev_key fields are confirmed across 4 events including the
+first-event-after-erase case (prev_key = self-reference `01110000`; next_key = device
+pre-allocates the predicted next slot even before any second event exists).
+
+**CRITICAL — strt[18] is a record-mode byte, NOT rectime_seconds (confirmed 2026-04-14):**
+Analysis of 15 distinct STRT records across the 4-9-26 ACH capture shows:
+- `flags=0xFFFE` (single-shot) → `strt[18] = 0x46` ('F') for EVERY event regardless of duration
+- `flags=0xFFFD` (continuous)  → `strt[18] = 0x0E` for EVERY event regardless of duration
+
+Do NOT use `strt[18]` for rectime.
+
+**Pre-trigger time is separate from record_time (confirmed 2026-04-14):**
+Blastware documentation states: "The default Time Scale is -0.25 second to 1 second — this
+negative number accounts for the pre-trigger set for compliance monitoring."  Therefore:
+- `record_time` (3.0 s) is POST-TRIGGER duration only
+- Pre-trigger = 0.25 s = 256 samples at 1024 sps (compliance monitoring standard default)
+- The pre-trigger field has NOT yet been located in the raw compliance config bytes
+- `_decode_a5_waveform` falls back to pretrig = 0.25 × sr from compliance standard
+- TODO: locate pretrig_time offset in ComplianceConfig — search around anchor or channel blocks
+
+The device bulk-streams zero-padded frames BEYOND the configured record window.  The
+viewer clips `displayCount = total_samples = pretrig + post_trig` to exclude this padding.
+
+**Validity checks in `_decode_a5_waveform`:**
+Check 1: `pretrig_samples >= total_samples` → invalid (original check).
+Check 2: STRT-derived rectime differs from `compliance_config.record_time` by more than 2×
+→ invalid.  Both failures fall back to the compliance-config derived values.
+`_decode_a5_waveform` logs `raw strt[0:21]` at WARNING level on any failure.
+Observed once (2026-04-14) with `strt[16:18] = 0x41 0x01` → pretrig=16641 (impossible).
+Root cause not yet identified — capture the warning log hex dump to diagnose.
+
 ### SUB 5A — end-of-stream signal (confirmed 2026-04-06)
 
 After streaming all waveform chunks, the device sends exactly **1 raw byte** in response to
@@ -189,6 +266,94 @@ silence). Only the initial variable-size chunks contain actual signal.
 Removed. Terminator detection is via `page_key == 0x0000` in `read_bulk_waveform_stream`,
 not frame index.
 
+### SUB 5A — re-probe at counter=0x1000 (DLE collision, FIXED 2026-04-15)
+
+**Root cause (confirmed from diagnostic output, desk-thump event key=01110000):**
+`bulk_waveform_params()` sets `p[3] = (counter >> 8) & 0xFF`.  For chunk 4, counter =
+`4 * 0x0400 = 0x1000`, so `p[3] = 0x10` — the DLE byte.  Because `build_5a_frame` writes
+params RAW (no DLE stuffing), the on-wire byte sequence contains a bare `0x10`.  The
+device DLE-decodes its own receive buffer: `10 00` (the p[3]/p[4] pair) is collapsed to
+`00`, so the counter field reads 0 — a probe request.  The device re-sends the initial
+probe response (containing the STRT record and first waveform bytes).
+
+**Effect:** In a 36-frame stream for key=01110000, fi=4 was a byte-for-byte duplicate of
+fi=0 (same db=1101B, same w[0:32] bytes, STRT present at w[10]).  The old code treated it
+as a regular chunk, decoded the STRT bytes as int16 samples (producing T=21587="ST",
+V=21586="RT"), and shifted the running byte alignment for all subsequent frames.
+
+**Fix (`_decode_a5_waveform`):** Check for STRT in every frame, not just fi==0.  Any
+non-fi=0 frame containing STRT is a re-probe — log it and skip (do NOT add to
+`all_chunks`).  Regular chunk path is reached only when `w.find(b"STRT") < 0`.
+
+**Note:** This DLE collision is key-specific.  For key=01110000 (`key4[2:4]=0x0000`),
+counter = `chunk_num * 0x0400`, so counter=0x1000 occurs at chunk 4 for every event with
+this key.  For other keys (e.g. key=0111245a, `key4[2:4]=0x245A`), the chunk counter
+formula `key4[2:4] + n*0x0400` produces different values; the collision only occurs when
+the high byte of any counter is 0x10.
+
+### SUB 5A — metadata false-positive (FIXED 2026-04-15)
+
+**Root cause (confirmed from diagnostic output):**
+The old metadata-frame test was `b"Project:" in w` (single anchor).  For the 36-frame
+desk-thump stream, fi=15 had `b"Project:"` at w[93] inside live ADC data — a coincidental
+4-byte pattern in the waveform.  The frame (134 live sample-sets) was incorrectly skipped.
+
+**Fix:** Require BOTH `b"Project:" in w` AND `b"Client:" in w` to classify a frame as
+metadata.  The real metadata frame (fi=6 in the desk-thump stream) contains both strings
+as part of the compliance-setup ASCII block; random ADC data is statistically unlikely to
+contain both 8-byte sequences.
+
+**Updated check in `_decode_a5_waveform`:**
+```python
+elif b"Project:" in w and b"Client:" in w:
+    log.info("_decode_a5_waveform: fi=%d skipped (metadata frame)", fi)
+    continue
+```
+
+### SUB 5A — 0xFF tail frames beyond record window (confirmed 2026-04-15)
+
+The device bulk-streams flash pages beyond the configured record window.  Un-written flash
+pages read as 0xFF.  Decoded as int16 LE, `0xFF 0xFF = -1`, which maps to ~0 in/s after
+the geo scale factor is applied — producing a visible flat-line at the end of the waveform.
+
+**Confirmed from raw capture analysis (desk-thump event key=01110000, 1024 sps,
+record_time=3.0 s, ach_inbound_20260412_231505):**
+- total_samples = 256 (pretrig) + 3072 (post) = 3328
+- A5 stream: 37 frames total; frames 8–35 are uniform 1036-byte 0xFF data (unwritten flash)
+- Actual ADC signal: frames 0 (probe) + 1–3 + 5 + 7 = 6 data chunks ≈ 815 sample-sets (0.80 s)
+- The desk-thump vibration was genuinely short; the remaining ~2.2 s of the record window
+  is unwritten flash (0xFF), not signal.  The flatline is physically correct.
+- After 0xFF tail clip: display = min(decoded, 3328) excludes the all-zeros post-record padding
+
+**Fix (two parts):**
+1. `_decode_a5_waveform` (Python): already returns `total_samples` alongside
+   `samples_decoded`; the field is populated from compliance config:
+   `total_samples = pretrig_samples + round(record_time * sample_rate)`.
+2. `sfm_webapp.html` (`_buildWaveformCharts`): `display = Math.min(decoded, total_samples)`;
+   `times` array and per-channel `samples` are both sliced to `display` length before
+   plotting — `(channels[ch] || []).slice(0, display)`.  Without this, the chart rendered
+   all `decoded` samples including the 0xFF tail.
+
+### SUB 5A — chunk frame header is 5 bytes, NOT 8 (CORRECTED 2026-04-15)
+
+**`_decode_a5_waveform` uses `wave = w[5:]` to strip the per-chunk frame header.**
+
+The header is 5 bytes: 2 counter bytes + 3 zero bytes.  The code previously used `w[8:]`
+(8-byte strip) — this was WRONG and discarded 3 bytes of real waveform data per frame,
+misaligning the channel decode for all frames after any non-multiple-of-8 frame.
+
+**Proof — "Standard Recording Setup" cross-frame continuity test (MITM capture 4-11-26):**
+The ASCII string `"Standard Recording Setup"` spans the A5[5]→A5[6] frame boundary:
+- A5[5].w last 2 bytes: `53 74` = `"St"` (end of "Standard")
+- A5[6].w[0:5] = `00 00 00 00 00` (5 null bytes = header)
+- A5[6].w[5:] begins with `61 6e 64` = `"and"` (start of "andard Recording Setup…")
+
+Only `header=5` produces the contiguous string `"Standard Recording Setup"`.
+`header=6/7/8` all produce broken text (tested exhaustively).
+
+**Also updated:** The probe frame (fi=0) strip of `w[10:]` is unchanged — the STRT magic
+itself is at `w[10]` inside the probe frame, which has a different 10-byte preamble.
+
 ### SUB 1E / 1F — event iteration null sentinel and token position (FIXED, do not re-introduce)
 
 **token_params bug (FIXED):** The token byte was at `params[6]` (wrong). Both 3-31-26 and
@@ -935,6 +1100,32 @@ call-home.
 
 ---
 
+## Known broken / deferred
+
+### Waveform chart Y-axis scaling (see GitHub issue)
+
+**The waveform chart in the web viewer shows incorrect amplitudes — DO NOT trust the Y-axis values.**
+
+PPV values reported by the system (stored in the DB, shown in event summaries) come from
+the **0C waveform record** computed on-device and are correct.  The issue is purely in the
+ADC→in/s conversion used to draw the chart.
+
+What we know:
+- Decoded ADC peaks from 5A (~30703–32661 counts) imply ~9× larger PPV than the 0C record reports
+  (e.g. Vert 5.8 in/s decoded vs 0.690 in/s from 0C for the same event)
+- ALL four channels show near-full-scale peaks, which is implausible for a desk-thump event
+  where Vert should dominate
+- The `max_range_geo` value in the compliance config is 6.206053 in/s (not 10.000 or 1.25
+  as displayed in the Blastware UI) — unclear whether this is an ADC full-scale or something else
+- The empirical full-scale implied by 0C data is ~0.736 in/s, not 6.206
+- Tried: LE vs BE decode, header=5 vs 8, float32 format — all produce near-full-scale peaks
+- Root cause unknown; likely requires a Blastware-generated waveform export for the same
+  event to reverse-engineer the correct scaling formula
+
+Tracking: **GitHub issue #TODO** (create before resuming this work)
+
+---
+
 ## What's next
 
 - **Database** — SQLite store for events + monitor log entries; dedup by key; queryable
@@ -944,3 +1135,4 @@ call-home.
 - Modem manager — push RV50/RV55 configs via Sierra Wireless API
 - RV55 DCD/DTR issue — newer RV55 firmware doesn't assert DCD by default; units don't
   resume monitoring after call-home disconnect (`--restart-monitoring` flag deferred)
+

bridges/ach_server.py

@@ -371,6 +371,7 @@ class AchSession:
                     full_waveform=True,
                     stop_after_index=stop_idx,
                     skip_waveform_for_keys=seen_keys if seen_keys else None,
+                    compliance_config=device_info.compliance_config if device_info else None,
                 )
 
                 # Filter to events whose keys we haven't saved before.
@@ -445,8 +446,19 @@ class AchSession:
                 # ── Persist to SQLite DB ─────────────────────────────────────
                 _session_start = datetime.datetime.now()
                 try:
+                    # Build waveform blobs for events that have full raw_samples
+                    _waveform_blobs = {}
+                    for _ev in new_events:
+                        if _ev._waveform_key and _ev.raw_samples:
+                            _blob = _build_waveform_blob(_ev)
+                            if _blob:
+                                _waveform_blobs[_ev._waveform_key.hex()] = _blob
+                    if _waveform_blobs:
+                        log.info("  [DB] waveform blobs prepared: %d", len(_waveform_blobs))
+
                     _ev_ins, _ev_skip = self.db.insert_events(
-                        new_events, serial=serial or self.peer, session_id=None
+                        new_events, serial=serial or self.peer, session_id=None,
+                        waveform_blobs=_waveform_blobs,
                     )
                     _ml_ins, _ml_skip = self.db.insert_monitor_log(
                         new_monitor_entries, session_id=None
@@ -599,6 +611,55 @@ def _event_to_dict(e: Event) -> dict:
     }
 
 
+def _build_waveform_blob(e: Event) -> Optional[str]:
+    """
+    Serialise a downloaded event's full waveform data as a JSON string for
+    storage in the DB waveform_blob column.
+
+    Returns the same shape as GET /device/event/{index}/waveform so the
+    waveform viewer can consume either source without modification.
+    Returns None if the event has no raw_samples (e.g. metadata-only download).
+    """
+    raw = e.raw_samples or {}
+    if not raw:
+        return None
+
+    pv = e.peak_values
+    peak_values = None
+    if pv:
+        # Key names must match sfm/server.py _serialise_peak_values() so the
+        # waveform viewer (which reads tran_in_s / vert_in_s / long_in_s) works
+        # identically in both live-device mode and DB mode.
+        peak_values = {
+            "tran_in_s":        pv.tran,
+            "vert_in_s":        pv.vert,
+            "long_in_s":        pv.long,
+            "micl_psi":         pv.micl,
+            "peak_vector_sum":  pv.peak_vector_sum,
+        }
+
+    ts = e.timestamp
+    timestamp_str = (
+        f"{ts.year:04d}-{ts.month:02d}-{ts.day:02d}T"
+        f"{ts.hour:02d}:{ts.minute:02d}:{ts.second:02d}"
+        if ts else None
+    )
+
+    blob = {
+        "index":           e.index,
+        "record_type":     e.record_type,
+        "timestamp":       timestamp_str,
+        "total_samples":   e.total_samples,
+        "pretrig_samples": e.pretrig_samples,
+        "rectime_seconds": e.rectime_seconds,
+        "samples_decoded": len(raw.get("Tran", [])),
+        "sample_rate":     e.sample_rate,
+        "peak_values":     peak_values,
+        "channels":        raw,
+    }
+    return json.dumps(blob)
+
+
 def _monitor_log_entry_to_dict(e: MonitorLogEntry) -> dict:
     return {
         "key":               e.key,

diagnose_5a_frames.py

@@ -0,0 +1,328 @@
+#!/usr/bin/env python3
+"""
+diagnose_5a_frames.py -- Frame-by-frame diagnostic for SUB 5A waveform streams.
+
+Usage:
+    python diagnose_5a_frames.py [--host HOST] [--port PORT] [--event INDEX]
+
+Connects to the device, downloads the waveform for the specified event (default 0 =
+most recently stored), and prints detailed per-frame info for every A5 response frame:
+
+  fi=N  | db=NNN B  w=NNN B  | "Project:" in db=[offsets]  in w=[offsets]  <-- METADATA if detected
+        w[0:32]  = <hex>
+        w[-8:]   = <hex>
+        [waveform bytes or ASCII snippet]
+
+Then shows:
+  - total non-metadata frames, total waveform bytes, total sample-sets decoded
+  - compliance-config expected vs decoded counts
+  - sample values at the flat-line onset region (~1700-1820)
+  - first near-zero run location (|T| < 20 for 10+ consecutive samples)
+
+Run with: python diagnose_5a_frames.py 2>&1 | tee /tmp/diag_output.txt
+"""
+
+from __future__ import annotations
+
+import argparse
+import logging
+import struct
+import sys
+
+# -- Setup logging -------------------------------------------------------------
+logging.basicConfig(
+    level=logging.WARNING,   # suppress library noise; we print our own output
+    format="%(asctime)s %(levelname)s %(name)s: %(message)s",
+    stream=sys.stderr,
+)
+
+from minimateplus import MiniMateClient
+from minimateplus.transport import TcpTransport
+
+log = logging.getLogger("diagnose")
+log.setLevel(logging.INFO)
+
+
+def decode_int16_sets(wave: bytes, n: int = 8) -> list[tuple[int, int, int, int]]:
+    """Decode up to n sample-sets from wave bytes as [T, V, L, M] int16 LE."""
+    sets = []
+    for i in range(min(n, len(wave) // 8)):
+        off = i * 8
+        t = struct.unpack_from("<h", wave, off)[0]
+        v = struct.unpack_from("<h", wave, off + 2)[0]
+        l = struct.unpack_from("<h", wave, off + 4)[0]
+        m = struct.unpack_from("<h", wave, off + 6)[0]
+        sets.append((t, v, l, m))
+    return sets
+
+
+def find_all(data: bytes, needle: bytes) -> list[int]:
+    """Return all offsets where needle appears in data."""
+    positions = []
+    start = 0
+    while True:
+        pos = data.find(needle, start)
+        if pos < 0:
+            break
+        positions.append(pos)
+        start = pos + 1
+    return positions
+
+
+def sep(label: str = "") -> None:
+    width = 80
+    if label:
+        pad = max(0, (width - len(label) - 2) // 2)
+        print(f"\n{'-' * pad} {label} {'-' * max(0, width - pad - len(label) - 2)}")
+    else:
+        print("-" * width)
+
+
+def diagnose(frames_data: list[bytes], compliance_config=None) -> None:
+    """Analyse all A5 frames and print diagnostic info."""
+
+    sep("PER-FRAME ANALYSIS")
+    print(f"Total A5 frames received: {len(frames_data)}")
+    print()
+
+    all_chunks: list[tuple[int, bytes]] = []   # (fi, wave_bytes)
+    cumulative_wave_bytes = 0
+
+    for fi, db in enumerate(frames_data):
+        w = db[7:]  # what _decode_a5_waveform sees (db[7:])
+
+        # Find "Project:" in both the full frame data and the w=db[7:] slice
+        proj_in_db = find_all(db, b"Project:")
+        proj_in_w  = find_all(w,  b"Project:")
+
+        # The live detector in client.py uses: b"Project:" in w
+        detected_as_metadata = bool(proj_in_w)
+
+        flag = " <-- METADATA (skipped)" if detected_as_metadata else ""
+        print(f"fi={fi:3d}  db={len(db):5d}B  w={len(w):5d}B  "
+              f"Project: in db={proj_in_db}  in w(db[7:])={proj_in_w}{flag}")
+
+        hex_head = w[:32].hex(' ')
+        hex_tail = w[-8:].hex(' ') if len(w) >= 8 else w.hex(' ')
+        print(f"       w[0:32]  = {hex_head}")
+        print(f"       w[-8:]   = {hex_tail}")
+
+        if fi == 0:
+            sp = w.find(b"STRT")
+            if sp >= 0:
+                strt = w[sp:sp + 21]
+                print(f"       STRT at w[{sp}]: {strt.hex(' ')}")
+                wave = w[sp + 21:]
+                if wave:
+                    sets = decode_int16_sets(wave, 4)
+                    print(f"       wave[sp+21:] first 4 sets (T,V,L,M): {sets}")
+                    all_chunks.append((fi, wave))
+                    cumulative_wave_bytes += len(wave)
+                    print(f"       cum_bytes={cumulative_wave_bytes}  cum_sets={cumulative_wave_bytes // 8}")
+            else:
+                print(f"       *** STRT NOT FOUND ***")
+
+        elif detected_as_metadata:
+            # Print the ASCII content to confirm this is the real metadata frame
+            try:
+                snippet = w.decode("ascii", errors="replace")
+                # Find the first 200 printable characters
+                printable = snippet[:200].replace("\x00", ".").replace("\r", "\n").replace("\n", "\n")
+                print(f"       ASCII: {repr(printable[:140])}")
+            except Exception as e:
+                print(f"       (decode error: {e})")
+
+        else:
+            # Regular chunk: strip 8-byte header
+            if len(w) >= 8:
+                wave = w[8:]
+                all_chunks.append((fi, wave))
+                cumulative_wave_bytes += len(wave)
+                sets = decode_int16_sets(wave, 4)
+                # Count near-zero Tran values
+                all_sets = decode_int16_sets(wave, len(wave) // 8)
+                nz = sum(1 for s in all_sets if abs(s[0]) < 20)
+                print(f"       wave[8:] first 4 sets: {sets}")
+                print(f"       cum_bytes={cumulative_wave_bytes}  cum_sets={cumulative_wave_bytes // 8}  "
+                      f"near-zero(|T|<20): {nz}/{len(all_sets)}")
+
+        print()
+
+    # -- Waveform value analysis ------------------------------------------------
+    sep("WAVEFORM DECODE")
+
+    cc_sr = 1024
+    cc_rt = None
+    pretrig = 256
+    total_expected = 0
+
+    if compliance_config:
+        cc_sr = compliance_config.sample_rate or 1024
+        cc_rt = compliance_config.record_time
+        pretrig = int(round(0.25 * cc_sr))
+        if cc_rt:
+            total_expected = pretrig + int(round(cc_rt * cc_sr))
+        print(f"Compliance: sr={cc_sr} sps  record_time={cc_rt} s  "
+              f"pretrig={pretrig}  total_expected={total_expected}")
+    else:
+        print("No compliance config -- using defaults: sr=1024, pretrig=256")
+
+    total_wave_bytes = sum(len(w) for _, w in all_chunks)
+    total_sets_raw = total_wave_bytes // 8
+    print(f"Non-metadata frames: {len(all_chunks)}  "
+          f"Total wave bytes: {total_wave_bytes}  "
+          f"Raw sample-sets: {total_sets_raw}")
+
+    # Alignment-corrected decode (matches _decode_a5_waveform exactly)
+    tran: list[int] = []
+    running_offset = 0
+    for fi, wave in all_chunks:
+        align = running_offset % 8
+        skip  = (8 - align) % 8
+        if skip > 0 and skip < len(wave):
+            usable = wave[skip:]
+        elif align == 0:
+            usable = wave
+        else:
+            running_offset += len(wave)
+            continue
+        n_usable = len(usable) // 8
+        for i in range(n_usable):
+            tran.append(struct.unpack_from("<h", usable, i * 8)[0])
+        running_offset += len(wave)
+
+    n_decoded = len(tran)
+    print(f"Alignment-corrected decoded Tran samples: {n_decoded}")
+    if compliance_config and cc_rt:
+        print(f"Expected: {total_expected}  Decoded: {n_decoded}  "
+              f"Excess (tail): {max(0, n_decoded - total_expected)}")
+
+    print()
+    print(f"First 16 Tran: {tran[:16]}")
+    if n_decoded >= 32:
+        print(f"Last  16 Tran: {tran[-16:]}")
+
+    # -- Flat-line onset search -------------------------------------------------
+    sep("FLAT-LINE ONSET (first run of 10+ consecutive |Tran| < 20)")
+
+    run_start = None
+    run_len = 0
+    onset_found = False
+    for i, v in enumerate(tran):
+        if abs(v) < 20:
+            if run_start is None:
+                run_start = i
+            run_len += 1
+        else:
+            if run_len >= 10:
+                t_ms = (run_start - pretrig) * 1000.0 / cc_sr
+                print(f"  First near-zero run: sample {run_start}-{run_start + run_len - 1}  "
+                      f"(t={t_ms:.1f}ms post-trigger)  length={run_len}")
+                onset_found = True
+                break
+            run_start = None
+            run_len = 0
+    else:
+        if run_len >= 10 and run_start is not None:
+            t_ms = (run_start - pretrig) * 1000.0 / cc_sr
+            print(f"  Near-zero run at end: sample {run_start}-{n_decoded - 1}  "
+                  f"(t={t_ms:.1f}ms post-trigger)  length={run_len}")
+            onset_found = True
+
+    if not onset_found:
+        print("  No near-zero run of 10+ samples found (waveform looks active throughout)")
+
+    # Print samples around the expected flat-line onset (~1700-1820)
+    if n_decoded >= 1700:
+        print()
+        print("Tran samples [1700:1820] (10 per line):")
+        for row_start in range(1700, min(1820, n_decoded), 10):
+            row = tran[row_start:row_start + 10]
+            t_ms_row = (row_start - pretrig) * 1000.0 / cc_sr
+            print(f"  [{row_start:4d}] (t={t_ms_row:6.1f}ms): {row}")
+    else:
+        print(f"  Only {n_decoded} samples decoded -- range 1700-1820 not available")
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description="Diagnose A5 5A waveform frames")
+    parser.add_argument("--host",  default="63.43.212.232", help="Device IP")
+    parser.add_argument("--port",  type=int, default=9034,  help="TCP port")
+    parser.add_argument("--event", type=int, default=0,     help="Event index (0=first stored)")
+    args = parser.parse_args()
+
+    print(f"Connecting to {args.host}:{args.port} ...")
+    print(f"Target event index: {args.event}")
+    print()
+
+    transport = TcpTransport(args.host, port=args.port)
+    with MiniMateClient(transport=transport) as client:
+        info = client.connect()
+        print(f"Device: serial={info.serial}  firmware={info.firmware_version}")
+        compliance_config = info.compliance_config
+        if compliance_config:
+            print(f"Compliance: sample_rate={compliance_config.sample_rate}  "
+                  f"record_time={compliance_config.record_time}")
+        print()
+
+        proto = client._proto
+        assert proto is not None
+
+        # -- Walk to the target event ------------------------------------------
+        log.info("Reading first event key (SUB 1E) ...")
+        first_key4, first_data8 = proto.read_event_first(token=0)
+        print(f"First event key: {first_key4.hex()}")
+
+        cur_key4   = first_key4
+        cur_data8  = first_data8
+        event_idx  = 0
+
+        while event_idx < args.event:
+            # 0A required before each 1F to establish device context
+            proto.read_waveform_header(cur_key4)
+            next_key4, next_data8 = proto.advance_event(browse=True)
+            if next_data8[4:8] == b"\x00\x00\x00\x00":
+                print(f"Only {event_idx + 1} events available; cannot reach index {args.event}")
+                return
+            cur_key4  = next_key4
+            cur_data8 = next_data8
+            event_idx += 1
+            print(f"  advanced to event {event_idx}: key={cur_key4.hex()}")
+
+        print(f"\nDownloading event {args.event}: key={cur_key4.hex()}")
+
+        # -- Full download sequence (matches get_events download-mode) ---------
+        log.info("0A: read_waveform_header ...")
+        proto.read_waveform_header(cur_key4)
+
+        log.info("1E(0xFE): arm device for 5A ...")
+        proto.read_event_first(token=0xFE)
+
+        log.info("0C: read_waveform_record ...")
+        wfm_raw = proto.read_waveform_record(cur_key4)
+        print(f"0C waveform record: {len(wfm_raw)} bytes")
+
+        log.info("1F(0xFE): arm 5A state machine ...")
+        arm_key4, _ = proto.advance_event(browse=False)
+        print(f"1F(arm) returned key: {arm_key4.hex()}")
+
+        log.info("POLLx3 ...")
+        for i in range(3):
+            proto.poll()
+            print(f"  POLL {i+1}/3 OK")
+
+        print(f"\nStarting 5A bulk stream for key={cur_key4.hex()} ...")
+        frames_data = proto.read_bulk_waveform_stream(
+            cur_key4,
+            stop_after_metadata=False,
+            max_chunks=2048,
+        )
+        print(f"5A complete: {len(frames_data)} A5 frames")
+        print()
+
+        # -- Run the diagnostic ------------------------------------------------
+        diagnose(frames_data, compliance_config)
+
+
+if __name__ == "__main__":
+    main()

minimateplus/client.py

@@ -448,7 +448,7 @@ class MiniMateClient:
         proto.confirm_erase_all()
         log.info("delete_all_events: erase confirmed — device memory cleared")
 
-    def get_events(self, full_waveform: bool = False, debug: bool = False, stop_after_index: Optional[int] = None, skip_waveform_for_keys: Optional[set] = None) -> list[Event]:
+    def get_events(self, full_waveform: bool = False, debug: bool = False, stop_after_index: Optional[int] = None, skip_waveform_for_keys: Optional[set] = None, compliance_config: Optional["ComplianceConfig"] = None) -> list[Event]:
         """
         Download all stored events from the device using the confirmed
         1E → 0A → 0C → 5A → 1F event-iterator protocol.
@@ -479,6 +479,7 @@ class MiniMateClient:
             ProtocolError: on unrecoverable communication failure.
         """
         proto = self._require_proto()
+        _compliance_config = compliance_config   # passed through to _decode_a5_waveform
 
         log.info("get_events: requesting first event (SUB 1E)")
         try:
@@ -603,12 +604,12 @@ class MiniMateClient:
                             "get_events: 5A full waveform download for key=%s", cur_key.hex()
                         )
                         a5_frames = proto.read_bulk_waveform_stream(
-                            cur_key, stop_after_metadata=False, max_chunks=128
+                            cur_key, stop_after_metadata=False, max_chunks=2048
                         )
                         if a5_frames:
                             a5_ok = True
                             _decode_a5_metadata_into(a5_frames, ev)
-                            _decode_a5_waveform(a5_frames, ev)
+                            _decode_a5_waveform(a5_frames, ev, compliance_config=_compliance_config)
                             log.info(
                                 "get_events: 5A decoded %d sample-sets",
                                 len((ev.raw_samples or {}).get("Tran", [])),
@@ -1311,6 +1312,7 @@ def _decode_a5_metadata_into(frames_data: list[bytes], event: Event) -> None:
 def _decode_a5_waveform(
     frames_data: list[bytes],
     event: Event,
+    compliance_config: Optional["ComplianceConfig"] = None,
 ) -> None:
     """
     Decode the raw 4-channel ADC waveform from a complete set of SUB 5A
@@ -1336,20 +1338,30 @@ def _decode_a5_waveform(
 
     ── Frame structure ──────────────────────────────────────────────────────────
     A5[0] (probe response):
-        db[7:]  = [11-byte header] [21-byte STRT record] [6-byte preamble] [waveform ...]
+        db[7:]  = [11-byte header] [21-byte STRT record] [waveform ...]
         STRT:     b'STRT' at offset 11, total 21 bytes
-                  +8  uint16 BE: total_samples (expected full-record sample-sets)
+                  +4..5  0xFF 0xFE (single-shot) or 0xFF 0xFD (continuous)
-                  +16 uint16 BE: pretrig_samples (pre-trigger sample count)
+                  +6..9  next_event_key4  (device pre-allocates next slot)
-                  +18 uint8:     rectime_seconds (record duration)
+                  +10..13 prev_event_key4
-        Preamble: 6 bytes after the STRT record (confirmed from 4-2-26 blast capture):
+                  +14..15 UNKNOWN (not total_samples)
-                  bytes 21-22: 0x00 0x00  (null padding)
+                  +16..17 UNKNOWN (not pretrig_samples)
-                  bytes 23-26: 0xFF × 4   (sync sentinel / alignment marker)
+                  +18    mode byte: 0x46 single-shot, 0x0E continuous
-        Waveform starts at strt_pos + 27 within db[7:].
+                  +19..20 0x00 0x00
+        Waveform starts immediately at strt_pos + 21 (no preamble).
+        NOTE: The original 4-2-26 blast capture appeared to show a 6-byte
+        "preamble" (00 00 ff ff ff ff) after the STRT record, but this was
+        actually the first ~0.75 sample-sets of quiet pre-trigger ADC data
+        misread as padding.  Confirmed 2026-04-14: bytes 21+ are raw waveform.
+        total_samples and pretrig_samples are NOT stored in the STRT record;
+        they are derived from the compliance config (the correct permanent source).
 
     A5[1..N] (chunk responses):
-        db[7:]  = [8-byte per-frame header] [waveform bytes ...]
+        db[7:]  = [5-byte per-frame header] [waveform bytes ...]
-        Header:   [ctr LE uint16, 0x00 × 6] — frame sequence counter
+        Header:   [ctr LE uint16, 0x00 × 3] — frame sequence counter + 3 null bytes
-        Waveform starts at byte 8 of db[7:].
+        Waveform starts at byte 5 of db[7:].
+        NOTE: Previously documented as 8-byte header — INCORRECT.  Confirmed 5 bytes
+        via "Standard Recording Setup" cross-frame continuity test on MITM capture
+        (4-11-26): A5[5] ends "St", A5[6].w[0:5] = 5 nulls, w[5:]= "andard…" ✓.
 
     ── Cross-frame alignment ────────────────────────────────────────────────────
     Frame waveform chunk sizes are NOT multiples of 8.  Naive concatenation
@@ -1357,11 +1369,13 @@ def _decode_a5_waveform(
     cumulative global byte offset; at each new frame, the starting alignment
     within the T,V,L,M cycle is (global_offset % 8).
 
-    Confirmed sizes from 4-2-26 (A5[0..8], skipping A5[7] metadata frame
+    Confirmed sizes from 4-2-26 blast capture (A5[0..8], metadata at A5[7]):
-    and A5[9] terminator):
         Frame 0: 934B  Frame 1: 963B  Frame 2: 946B  Frame 3: 960B
         Frame 4: 952B  Frame 5: 946B  Frame 6: 941B  Frame 8: 992B
     — none are multiples of 8.
+    NOTE: Metadata frame position is variable — at fi==7 for blast events
+    (4-2-26 capture) and fi==6 for desk-thump events (2026-04-14 confirmed).
+    The dynamic b"Project:" detection handles both cases.
 
     ── Modifies event in-place. ─────────────────────────────────────────────────
     """
@@ -1378,27 +1392,48 @@ def _decode_a5_waveform(
 
     # STRT record layout (21 bytes, offsets relative to b'STRT'):
     #   +0..3   magic  b'STRT'
-    #   +8..9   uint16 BE  total_samples  (full-record expected sample-set count)
+    #   +4..5   0xFF 0xFE (single-shot) or 0xFF 0xFD (continuous)
-    #   +16..17 uint16 BE  pretrig_samples
+    #   +6..9   next_event_key4  (NOT current key — device pre-allocates next)
-    #   +18     uint8      rectime_seconds
+    #   +10..13 prev_event_key4
+    #   +14..15 UNKNOWN — confirmed NOT total_samples (confirmed 2026-04-14)
+    #   +16..17 UNKNOWN — confirmed NOT pretrig_samples (confirmed 2026-04-14)
+    #   +18     mode byte: 0x46='F' single-shot, 0x0E continuous — NOT rectime
+    #   +19..20 0x00 0x00
+    # Bytes 21+ are raw ADC waveform samples — no preamble.
+    # total_samples / pretrig_samples are NOT stored in STRT at all.
+    # The compliance config fallback is the correct permanent source.
     strt = w0[strt_pos : strt_pos + 21]
     if len(strt) < 21:
         log.warning("_decode_a5_waveform: STRT record truncated (%dB)", len(strt))
         return
 
-    total_samples   = struct.unpack_from(">H", strt, 8)[0]
+    log.info(
-    pretrig_samples = struct.unpack_from(">H", strt, 16)[0]
+        "_decode_a5_waveform: STRT raw[0:21]: %s",
-    rectime_seconds = strt[18]
+        strt.hex(' '),
-
-    event.total_samples   = total_samples
-    event.pretrig_samples = pretrig_samples
-    event.rectime_seconds = rectime_seconds
-
-    log.debug(
-        "_decode_a5_waveform: STRT total_samples=%d pretrig=%d rectime=%ds",
-        total_samples, pretrig_samples, rectime_seconds,
     )
 
+    # STRT bytes +14..17 are unknown fields — confirmed NOT total/pretrig_samples
+    # (2026-04-14).  total_samples and pretrig_samples are derived from the
+    # compliance config, which is the correct permanent source.
+    _strt_invalid = True
+    _sample_rate_default = 1024
+    total_samples   = 0
+    pretrig_samples = 0
+    rectime_seconds = 0
+
+    log.info(
+        "_decode_a5_waveform: STRT flags=0x%04X  next_key=%s  prev_key=%s  "
+        "mode=0x%02X  → using compliance-config for total/pretrig",
+        struct.unpack_from(">H", strt, 4)[0],
+        strt[6:10].hex(),
+        strt[10:14].hex(),
+        strt[18],
+    )
+
+    event.total_samples   = 0   # will be overwritten by compliance-config fallback below
+    event.pretrig_samples = 0
+    event.rectime_seconds = 0
+
     # ── Collect per-frame waveform bytes with global offset tracking ─────────
     # global_offset is the cumulative byte count across all frames, used to
     # compute the channel alignment at each frame boundary.
@@ -1408,27 +1443,65 @@ def _decode_a5_waveform(
     for fi, db in enumerate(frames_data):
         w = db[7:]
 
-        # A5[0]: waveform begins after the 21-byte STRT record and 6-byte preamble.
+        # ── Probe frames (fi==0 AND any re-probe the device sends mid-stream) ────
-        # Layout: STRT(21B) + null-pad(2B) + 0xFF sentinel(4B) = 27 bytes total.
+        # A5[0] always contains the STRT record.  For event key 0x01110000,
-        if fi == 0:
+        # chunk 4 (counter=0x1000) has 0x10 in the counter high byte; the device
+        # DLE-decodes the params and sees counter=0x0000 (probe), so it responds
+        # with a duplicate probe frame containing the same STRT.  The diagnostic
+        # from 2026-04-15 confirmed this: fi=4 was byte-for-byte identical to fi=0
+        # (same db length 1101B, same STRT at w[10], same first 32 bytes).
+        #
+        # Handling: any frame — not just fi==0 — that contains the STRT magic is
+        # treated as a probe frame.  Waveform starts at strt_pos + 21 (no preamble).
+        # Re-probe frames are complete duplicates of fi=0 (device re-sends the
+        # beginning of the event), so their post-STRT waveform bytes are DROPPED
+        # to avoid injecting duplicate data into the stream.
         sp = w.find(b"STRT")
-            if sp < 0:
+        if sp >= 0:
+            if fi == 0:
+                wave = w[sp + 21 :]
+                log.info(
+                    "_decode_a5_waveform: A5[0] probe — STRT at w[%d], "
+                    "waveform starts at sp+21; first 24 wave bytes: %s",
+                    sp, wave[:24].hex(' '),
+                )
+            else:
+                # Re-probe frame: device re-sent probe in response to a chunk
+                # request whose counter byte happened to be 0x10 (DLE).
+                # The post-STRT bytes are a duplicate of the initial waveform
+                # — drop this frame entirely to avoid double-counting data.
+                log.info(
+                    "_decode_a5_waveform: fi=%d re-probe (STRT at w[%d]) — "
+                    "skipped (duplicate probe response from device)",
+                    fi, sp,
+                )
                 continue
-            wave = w[sp + 27 :]
 
-        # Frame 7 carries event-time metadata strings ("Project:", "Client:", …)
+        # Metadata frame: contains BOTH "Project:" and "Client:" strings.
-        # and no waveform ADC data.
+        # Requiring two compliance anchors prevents false positives where ADC
-        elif fi == 7:
+        # bytes accidentally spell "Project:" (confirmed false positive at fi=15
+        # in the 2026-04-15 desk-thump download — only "Project:" appeared there,
+        # not "Client:").  The real metadata frame always contains both.
+        # This is the same anchor used by stop_after_metadata in
+        # read_bulk_waveform_stream (which only checks "Project:" — see note
+        # there about the asymmetry: stopping early is fine with one anchor,
+        # but skipping a waveform frame requires higher confidence).
+        elif b"Project:" in w and b"Client:" in w:
+            log.info("_decode_a5_waveform: fi=%d skipped (metadata frame)", fi)
             continue
 
         # Terminator frames have page_key=0x0000 and are excluded upstream
         # (read_bulk_waveform_stream returns early on page_key==0).
         # No hardcoded frame-index skip here — all non-metadata frames are data.
         else:
-            # Strip the 8-byte per-frame header (ctr + 6 zero bytes)
+            # Strip the 5-byte per-frame header (ctr[2] + 3 zero bytes + 1 flag byte).
-            if len(w) < 8:
+            # Confirmed 2026-04-15 via "Standard Recording Setup" cross-frame continuity
+            # test on MITM capture (4-11-26): A5[5] ends with "St", A5[6].w[0:5] are
+            # 5 null bytes, w[5:] begins with "andard Recording Setup…" — contiguous iff
+            # header=5.  Previously documented as 8 bytes — INCORRECT.
+            if len(w) < 5:
                 continue
-            wave = w[8:]
+            wave = w[5:]
 
         if len(wave) < 2:
             continue
@@ -1490,10 +1563,28 @@ def _decode_a5_waveform(
 
         running_offset += len(wave)
 
+    n_decoded_total = len(tran)
     log.debug(
         "_decode_a5_waveform: decoded %d alignment-corrected sample-sets "
         "(skipped %d due to frame boundary misalignment)",
-        len(tran), n_sets - len(tran),
+        n_decoded_total, n_sets - n_decoded_total,
+    )
+    # Log first 16 and last 8 samples for every channel — essential for
+    # validating decoder output and diagnosing flatline / misalignment issues.
+    _N = min(16, n_decoded_total)
+    _L = max(0, n_decoded_total - 8)
+    log.info(
+        "_decode_a5_waveform: first %d samples — "
+        "Tran=%s  Vert=%s  Long=%s  Mic=%s",
+        _N,
+        tran[:_N], vert[:_N], long_[:_N], mic[:_N],
+    )
+    if n_decoded_total > 16:
+        log.info(
+            "_decode_a5_waveform: last 8 samples (idx %d–%d) — "
+            "Tran=%s  Vert=%s  Long=%s  Mic=%s",
+            _L, n_decoded_total - 1,
+            tran[_L:], vert[_L:], long_[_L:], mic[_L:],
         )
 
     event.raw_samples = {
@@ -1503,6 +1594,64 @@ def _decode_a5_waveform(
         "Mic":  mic,
     }
 
+    # ── Derive pretrig/total from compliance config (always — STRT doesn't store them) ──
+    # total_samples and pretrig_samples are not stored in the STRT record (confirmed
+    # 2026-04-14).  They are derived from compliance config record_time × sample_rate.
+    # _strt_invalid is always True; this block always runs.
+    #
+    # Formula:
+    #   post_trig  = record_time (s) × sample_rate (sps)
+    #   pretrig    = decoded_samples − post_trig
+    #
+    # This gives the pre-trigger window length, which correctly places t=0 in the
+    # waveform. If compliance_config is not available, leave pretrig=0 (viewer shows
+    # full waveform starting at t=0 — better than a crash or garbage).
+    n_decoded = len(tran)
+    if _strt_invalid:
+        if compliance_config is not None:
+            cc_sr = compliance_config.sample_rate or 1024
+            cc_rt = compliance_config.record_time
+            # Pre-trigger time is a separate device setting from Record Time.
+            # Blastware documentation confirms the compliance monitoring standard
+            # is 0.25 seconds pre-trigger ("the default Time Scale is -0.25 to 1
+            # second — this negative number accounts for the pre-trigger set for
+            # compliance monitoring").
+            # The pre-trigger field has not yet been located in the raw compliance
+            # config bytes; 0.25 s is used as the best-known default until it is
+            # decoded.  TODO: locate pretrig_time in ComplianceConfig bytes.
+            _PRETRIG_SECONDS_DEFAULT = 0.25
+            derived_pretrig = int(round(_PRETRIG_SECONDS_DEFAULT * cc_sr))
+            if cc_rt and cc_rt > 0:
+                post_trig_samples = int(round(cc_rt * cc_sr))
+                # Clip total to pretrig + post_trig so the viewer doesn't show the
+                # zero-padded tail frames the device appends beyond the record window.
+                event.total_samples   = derived_pretrig + post_trig_samples
+                event.pretrig_samples = derived_pretrig
+                event.rectime_seconds = int(round(cc_rt))
+                log.info(
+                    "_decode_a5_waveform: pretrig=%d (%.2fs compliance default)  "
+                    "post_trig=%d  total=%d  record_time=%.1fs  "
+                    "sr=%d sps  decoded=%d samples",
+                    derived_pretrig, _PRETRIG_SECONDS_DEFAULT,
+                    post_trig_samples, event.total_samples,
+                    cc_rt, cc_sr, n_decoded,
+                )
+            else:
+                event.total_samples   = n_decoded
+                event.pretrig_samples = derived_pretrig
+                log.warning(
+                    "_decode_a5_waveform: STRT invalid, compliance config missing "
+                    "record_time — pretrig=%d (%.2fs default), total=decoded %d",
+                    derived_pretrig, _PRETRIG_SECONDS_DEFAULT, n_decoded,
+                )
+        else:
+            event.total_samples = n_decoded
+            log.warning(
+                "_decode_a5_waveform: STRT invalid, no compliance config available "
+                "— pretrig left as 0, total set to decoded count %d",
+                n_decoded,
+            )
+
 
 def _extract_record_type(data: bytes) -> Optional[str]:
     """
@@ -2127,20 +2276,4 @@ def _decode_monitor_status(data: bytes) -> MonitorStatus:
     # Payload length varies (46–49 bytes) but the battery/memory block is always
     # the last 10 bytes. No checksum byte — it was stripped by S3FrameParser.
     #
-    #   section[-10:-8]   battery  × 100   uint16 BE   0x02A8 = 6.80 V
+    #   section[-1
-    #   section[-8 :-4]   memory_total     uint32 BE   ≈ 960 KB on BE11529
-    #   section[-4:]      memory_free      uint32 BE   decreases as events fill
-    #
-    # Confirmed stable across IDLE (46b), MONITORING (48-49b) variants.
-    if len(section) >= 10:
-        batt_raw     = struct.unpack(">H", section[-10:-8])[0]
-        battery_v    = batt_raw / 100.0
-        memory_total = struct.unpack(">I", section[-8:-4])[0]
-        memory_free  = struct.unpack(">I", section[-4:])[0]
-
-    return MonitorStatus(
-        is_monitoring=is_monitoring,
-        battery_v=battery_v,
-        memory_total=memory_total,
-        memory_free=memory_free,
-    )

sfm/database.py

@@ -81,6 +81,7 @@ CREATE TABLE IF NOT EXISTS events (
     sample_rate             INTEGER,
     record_type             TEXT,                   -- "single_shot" | "continuous"
     false_trigger           INTEGER NOT NULL DEFAULT 0,  -- 0=no, 1=yes (manual flag)
+    waveform_blob           TEXT,                       -- JSON waveform response (channels + metadata)
     created_at              TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%SZ', 'now')),
     UNIQUE(serial, timestamp)
 );
@@ -216,6 +217,17 @@ class SeismoDb:
             """)
             log.info("_migrate: monitor_log table rebuilt OK")
 
+        # Migration 3: add waveform_blob column to events (nullable TEXT).
+        # ALter TABLE ADD COLUMN is safe in SQLite for nullable columns — no rebuild needed.
+        col_names = {
+            row[1]
+            for row in conn.execute("PRAGMA table_info(events)").fetchall()
+        }
+        if "waveform_blob" not in col_names:
+            log.info("_migrate: adding waveform_blob column to events")
+            conn.execute("ALTER TABLE events ADD COLUMN waveform_blob TEXT")
+            log.info("_migrate: waveform_blob column added OK")
+
     @staticmethod
     def _iso(dt: Optional[datetime.datetime]) -> Optional[str]:
         return dt.isoformat() if dt is not None else None
@@ -282,12 +294,19 @@ class SeismoDb:
         *,
         serial: str,
         session_id: Optional[str] = None,
+        waveform_blobs: Optional[dict[str, str]] = None,
     ) -> tuple[int, int]:
         """
         Insert triggered events. Silently skips duplicates (serial+timestamp).
         Returns (inserted, skipped).
+
+        waveform_blobs: optional mapping of waveform_key (hex str) → JSON string
+        containing the full waveform response (channels + metadata).  When provided,
+        the blob is stored alongside the event row and is retrievable via
+        GET /db/events/{id}/waveform.
         """
         inserted = skipped = 0
+        blobs = waveform_blobs or {}
         with self._connect() as conn:
             for ev in events:
                 key = ev._waveform_key.hex() if ev._waveform_key else None
@@ -307,6 +326,7 @@ class SeismoDb:
 
                 pv   = ev.peak_values
                 pi   = ev.project_info
+                blob = blobs.get(key)
 
                 try:
                     conn.execute(
@@ -315,8 +335,8 @@ class SeismoDb:
                             (id, serial, waveform_key, session_id, timestamp,
                              tran_ppv, vert_ppv, long_ppv, peak_vector_sum, mic_ppv,
                              project, client, operator, sensor_location,
-                             sample_rate, record_type)
+                             sample_rate, record_type, waveform_blob)
-                        VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+                        VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
                         """,
                         (
                             self._new_id(), serial, key, session_id, ts,
@@ -331,6 +351,7 @@ class SeismoDb:
                             pi.sensor_location if pi else None,
                             ev.sample_rate,
                             ev.record_type,
+                            blob,
                         ),
                     )
                     inserted += 1
@@ -387,6 +408,23 @@ class SeismoDb:
             )
         return cur.rowcount > 0
 
+    def get_event_waveform(self, event_id: str) -> tuple[bool, Optional[str]]:
+        """
+        Return (found, waveform_blob) for a given event UUID.
+
+        found=False means the event row doesn't exist.
+        found=True, blob=None means the event exists but has no stored waveform
+        (e.g. downloaded before waveform storage was implemented).
+        found=True, blob=<str> means the full waveform JSON is available.
+        """
+        with self._connect() as conn:
+            row = conn.execute(
+                "SELECT waveform_blob FROM events WHERE id = ?", (event_id,)
+            ).fetchone()
+        if row is None:
+            return False, None
+        return True, row["waveform_blob"]
+
     # ── Monitor log ───────────────────────────────────────────────────────────
 
     def insert_monitor_log(

sfm/server.py

@@ -662,7 +662,11 @@ def device_event_waveform(
             with _build_client(port, baud, host, tcp_port, timeout=120.0) as client:
                 info = client.connect()
                 # stop_after_index avoids downloading events beyond the one requested.
-                events = client.get_events(full_waveform=True, stop_after_index=index)
+                events = client.get_events(
+                    full_waveform=True,
+                    stop_after_index=index,
+                    compliance_config=info.compliance_config if info else None,
+                )
                 matching = [ev for ev in events if ev.index == index]
                 return matching[0] if matching else None, info
         ev, info = _run_with_retry(_do, is_tcp=_is_tcp(host))
@@ -689,13 +693,22 @@ def device_event_waveform(
     if sample_rate is None and info.compliance_config:
         sample_rate = info.compliance_config.sample_rate
 
+    # Recompute rectime_seconds using the actual sample rate now that we have it.
+    # _decode_a5_waveform used 1024 sps as default; override if device says otherwise.
+    # strt[18] is a record-mode byte (0x46 / 0x0E), NOT rectime in seconds.
+    rectime_seconds = ev.rectime_seconds
+    if (ev.total_samples is not None and ev.pretrig_samples is not None
+            and sample_rate and sample_rate > 0):
+        post_trig = max(0, ev.total_samples - ev.pretrig_samples)
+        rectime_seconds = round(post_trig / sample_rate, 2)
+
     result = {
         "index":           ev.index,
         "record_type":     ev.record_type,
         "timestamp":       _serialise_timestamp(ev.timestamp),
         "total_samples":   ev.total_samples,
         "pretrig_samples": ev.pretrig_samples,
-        "rectime_seconds": ev.rectime_seconds,
+        "rectime_seconds": rectime_seconds,
         "samples_decoded": samples_decoded,
         "sample_rate":     sample_rate,
         "peak_values":     _serialise_peak_values(ev.peak_values),
@@ -1006,6 +1019,41 @@ def db_set_false_trigger(
     return {"status": "ok", "event_id": event_id, "false_trigger": value}
 
 
+@app.get("/db/events/{event_id}/waveform")
+def db_event_waveform(event_id: str) -> dict:
+    """
+    Return the stored waveform blob for a DB event.
+
+    The response shape is identical to GET /device/event/{index}/waveform so the
+    waveform viewer can consume either source without modification:
+      - total_samples, pretrig_samples, rectime_seconds, samples_decoded
+      - sample_rate
+      - peak_values  (tran_in_s, vert_in_s, long_in_s, micl_psi, peak_vector_sum)
+      - channels     ({"Tran": [...], "Vert": [...], "Long": [...], "Mic": [...]})
+
+    Returns 404 if the event doesn't exist, 422 if the event exists but has no
+    stored waveform (downloaded before waveform storage was implemented).
+    """
+    import json as _json
+    db   = _get_db()
+    found, blob_str = db.get_event_waveform(event_id)
+    if not found:
+        raise HTTPException(status_code=404, detail=f"Event {event_id} not found")
+    if blob_str is None:
+        raise HTTPException(
+            status_code=422,
+            detail=(
+                f"Event {event_id} has no stored waveform. "
+                "Waveform storage requires ACH server v0.11+. "
+                "Re-download the event from the device to backfill."
+            ),
+        )
+    try:
+        return _json.loads(blob_str)
+    except Exception as exc:
+        raise HTTPException(status_code=500, detail=f"Waveform blob corrupt: {exc}") from exc
+
+
 @app.get("/db/monitor_log")
 def db_monitor_log(
     serial:  Optional[str] = Query(None, description="Filter by unit serial"),

sfm/sfm_webapp.html

@@ -548,6 +548,18 @@
     .ft-toggle-btn:hover { border-color: var(--red); color: var(--red); }
     .ft-toggle-btn.flagged { border-color: var(--red); color: var(--red); background: rgba(248,81,73,0.1); }
 
+    .wf-btn {
+      background: none;
+      border: 1px solid var(--border);
+      border-radius: var(--radius);
+      color: var(--accent);
+      cursor: pointer;
+      font-size: 13px;
+      padding: 1px 6px;
+      line-height: 1;
+    }
+    .wf-btn:hover { background: rgba(56,139,253,0.15); border-color: var(--accent); }
+
     .db-empty {
       color: var(--text-mute);
       font-size: 13px;
@@ -770,6 +782,12 @@
     <button class="btn btn-ghost" id="load-btn" onclick="loadWaveform()" disabled>Load Waveform</button>
     <button class="btn btn-ghost" id="prev-btn" onclick="stepEvent(-1)" disabled>◀</button>
     <button class="btn btn-ghost" id="next-btn" onclick="stepEvent(+1)" disabled>▶</button>
+    <label style="display:flex;align-items:center;gap:5px;font-size:12px;color:var(--fg-muted);cursor:pointer;margin-left:4px"
+           title="Bypass server cache and re-download from device. Checking this auto-reloads if a waveform is already displayed.">
+      <input type="checkbox" id="force-reload" style="accent-color:#1f6feb"
+             onchange="if(this.checked && lastWaveformData !== null) loadWaveform()" />
+      Force&nbsp;reload
+    </label>
     <div class="event-chips" id="event-chips"></div>
   </div>
 
@@ -781,6 +799,14 @@
     <div class="pk"><div class="pk-label">PVS</div><div class="pk-value pk-pvs"  id="pk-pvs">—</div></div>
   </div>
 
+  <!-- Debug panel: raw ADC sample readout for diagnosing decode issues -->
+  <div id="debug-panel" style="display:none; background:#0d1117; border-bottom:1px solid #21262d;
+       padding:5px 16px; font-family:monospace; font-size:11px; color:#6e7681; line-height:1.8">
+    <span style="float:right; cursor:pointer; color:#484f58; text-decoration:underline"
+          onclick="document.getElementById('debug-panel').style.display='none'">hide</span>
+    <div id="debug-content"></div>
+  </div>
+
   <div id="waveform-area" style="flex:1; overflow-y:auto;">
     <div id="empty-state">
       <svg width="40" height="40" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5">
@@ -921,6 +947,7 @@
       <table class="db-table" id="hist-table">
         <thead>
           <tr>
+            <th></th>
             <th>Timestamp</th>
             <th>Serial</th>
             <th>Tran (in/s)</th>
@@ -1038,6 +1065,7 @@ let eventList     = [];
 let currentEvent  = 0;
 let charts        = {};
 let geoRange      = 6.206;
+let lastWaveformData = null;   // last successfully rendered waveform payload
 const DBL_REF     = 2.9e-9;   // 20 µPa in psi — reference pressure for dBL
 const CHANNEL_COLORS = { Tran:'#58a6ff', Vert:'#3fb950', Long:'#d29922', Mic:'#bc8cff' };
 
@@ -1500,12 +1528,13 @@ function updatePeaksBar(ev) {
 async function loadWaveform() {
   if (!devHost()) { setStatus('Enter device host first.', 'error'); return; }
   const idx   = currentEvent;
+  const force = document.getElementById('force-reload')?.checked ? '&force=true' : '';
   document.getElementById('load-btn').disabled = true;
   setStatus('Fetching waveform…', 'loading');
 
   let data;
   try {
-    const r = await fetch(`${api()}/device/event/${idx}/waveform?${deviceParams()}`);
+    const r = await fetch(`${api()}/device/event/${idx}/waveform?${deviceParams()}${force}`);
     if (!r.ok) { const e = await r.json().catch(()=>({})); throw new Error(e.detail || r.statusText); }
     data = await r.json();
   } catch(e) {
@@ -1514,52 +1543,57 @@ async function loadWaveform() {
     return;
   }
 
+  lastWaveformData = data;
   renderWaveform(data);
   document.getElementById('load-btn').disabled = false;
 }
 
-function renderWaveform(data) {
+// ── Shared waveform chart builder ──────────────────────────────────────────────
+// Renders waveform channel charts into chartsEl, destroys+replaces instances in
+// chartsStore.  emptyEl (optional) is shown/hidden based on decoded sample count.
+function _buildWaveformCharts(data, chartsEl, emptyEl, chartsStore) {
   const sr      = data.sample_rate || 1024;
   const pretrig = data.pretrig_samples || 0;
   const decoded = data.samples_decoded || 0;
-  const total   = data.total_samples || decoded;
+  // Clip display to total_samples (pretrig + post_trig from compliance config).
+  // The device bulk-streams zero-padded (0xFF = -1) frames beyond the configured
+  // record window; without clipping these appear as a flat line at ~0 in/s past
+  // the end of the actual recording.  Confirmed 2026-04-15: a 36-frame 5A stream
+  // for a 3.25s event (total_samples=3328) contained 19 trailing all-0xFF frames
+  // (2457 extra samples) that caused a visible flat-line in the waveform display.
+  const total   = (data.total_samples && data.total_samples > 0) ? data.total_samples : decoded;
+  const display = Math.min(decoded, total);
   const channels = data.channels || {};
 
-  // Status bar
+  // Destroy old chart instances
-  const bar = document.getElementById('status-bar');
+  Object.values(chartsStore).forEach(c => c.destroy());
-  bar.innerHTML = '';
+  for (const k in chartsStore) delete chartsStore[k];
-  bar.className = 'ok';
-  const ts = data.timestamp;
-  bar.textContent = ts ? `Event #${data.index}  —  ${ts.display}    ` : `Event #${data.index}    `;
-  addPill(`${data.record_type || '?'}`);
-  addPill(`${sr} sps`);
-  addPill(`${decoded.toLocaleString()} / ${total.toLocaleString()} samples`);
-  addPill(`pretrig ${pretrig}`);
-  addPill(`${data.rectime_seconds ?? '?'} s`);
 
   if (decoded === 0) {
-    document.getElementById('empty-state').style.display = 'flex';
+    if (emptyEl) {
-    document.getElementById('empty-state').querySelector('p').textContent =
+      emptyEl.style.display = 'flex';
-      data.record_type === 'Waveform'
+      const p = emptyEl.querySelector('p');
+      if (p) p.textContent = data.record_type === 'Waveform'
         ? 'No samples decoded — check server logs'
         : `Record type "${data.record_type}" — waveform not supported yet`;
-    document.getElementById('charts').style.display = 'none';
+    }
-    Object.values(charts).forEach(c => c.destroy()); charts = {};
+    chartsEl.style.display = 'none';
+    chartsEl.innerHTML = '';
     return;
   }
 
-  const times = Array.from({length: decoded}, (_, i) => ((i - pretrig) / sr * 1000).toFixed(2));
+  const times = Array.from({length: display}, (_, i) => ((i - pretrig) / sr * 1000).toFixed(2));
-  document.getElementById('empty-state').style.display = 'none';
+  if (emptyEl) emptyEl.style.display = 'none';
-  const chartsDiv = document.getElementById('charts');
+  chartsEl.style.display = 'flex';
-  chartsDiv.style.display = 'flex';
+  chartsEl.style.flexDirection = 'column';
-  chartsDiv.innerHTML = '';
+  chartsEl.style.gap = '8px';
-  Object.values(charts).forEach(c => c.destroy()); charts = {};
+  chartsEl.innerHTML = '';
 
   const micPeakPsi = data.peak_values?.micl_psi ?? null;
 
   for (const [ch, color] of Object.entries(CHANNEL_COLORS)) {
-    const samples = channels[ch];
+    const samples = (channels[ch] || []).slice(0, display);
-    if (!samples || samples.length === 0) continue;
+    if (samples.length === 0) continue;
 
     const isGeo = ch !== 'Mic';
     let plotData, peakLabel, yUnit, ttFmt, tickFmt;
@@ -1605,9 +1639,9 @@ function renderWaveform(data) {
     const cw = document.createElement('div');
     cw.className = 'chart-canvas-wrap';
     const canvas = document.createElement('canvas');
-    cw.appendChild(canvas); wrap.appendChild(cw); chartsDiv.appendChild(wrap);
+    cw.appendChild(canvas); wrap.appendChild(cw); chartsEl.appendChild(wrap);
 
-    charts[ch] = new Chart(canvas, {
+    chartsStore[ch] = new Chart(canvas, {
       type: 'line',
       data: { labels: rTimes, datasets: [{ data: rData, borderColor: color, borderWidth: 1, pointRadius: 0, tension: 0 }] },
       options: {
@@ -1642,6 +1676,64 @@ function renderWaveform(data) {
   }
 }
 
+function renderWaveform(data) {
+  const sr      = data.sample_rate || 1024;
+  const pretrig = data.pretrig_samples || 0;
+  const decoded = data.samples_decoded || 0;
+  const total   = data.total_samples || decoded;
+  lastWaveformData = data;
+
+  // Status bar
+  const bar = document.getElementById('status-bar');
+  bar.innerHTML = '';
+  bar.className = 'ok';
+  const ts = data.timestamp;
+  bar.textContent = ts ? `Event #${data.index}  —  ${ts.display}    ` : `Event #${data.index}    `;
+  addPill(`${data.record_type || '?'}`);
+  addPill(`${sr} sps`);
+  addPill(`${decoded.toLocaleString()} / ${total.toLocaleString()} samples`);
+  addPill(`pretrig ${pretrig}`);
+  addPill(`${data.rectime_seconds ?? '?'} s`);
+
+  _buildWaveformCharts(data, document.getElementById('charts'), document.getElementById('empty-state'), charts);
+  updateDebugPanel(data);
+}
+
+// ── Debug panel population ─────────────────────────────────────────────────────
+function _fillDebugPanel(data, dbg, cont) {
+  if (!dbg || !cont) return;
+  const channels = data.channels || {};
+  const pv       = data.peak_values || {};
+  const scale    = geoRange / 32767;
+  const geoChans = ['Tran', 'Vert', 'Long'];
+
+  let html = '<div style="display:flex;gap:24px;flex-wrap:wrap;">';
+  for (const ch of [...geoChans, 'Mic']) {
+    const raw    = (channels[ch] || []).slice(0, 8);
+    if (raw.length === 0) continue;
+    const maxAbs = Math.max(...raw.map(Math.abs));
+    const keyMap = { Tran:'tran_in_s', Vert:'vert_in_s', Long:'long_in_s' };
+    const p0c    = ch !== 'Mic' ? (pv[keyMap[ch]] ?? null) : null;
+    const src    = p0c !== null ? `<span style="color:#3fb950">0C=${p0c.toFixed(4)}</span>`
+                                : `<span style="color:#e3b341">Math.max≈${(maxAbs*scale).toFixed(4)}</span>`;
+    html += `<div><span style="color:#8b949e">${ch} raw[0:8]:</span> <span style="color:#c9d1d9">${raw.join(', ')}</span>  peak: ${src}</div>`;
+  }
+  html += '</div>';
+
+  const nullPeaks = geoChans.filter(ch => (pv[{ Tran:'tran_in_s', Vert:'vert_in_s', Long:'long_in_s' }[ch]] ?? null) === null);
+  if (nullPeaks.length > 0) {
+    html += `<div style="color:#e3b341;margin-top:2px">⚠ peak0C null for: ${nullPeaks.join(', ')} — peaks shown are Math.max of waveform samples, not 0C record</div>`;
+  }
+  html += `<div style="color:#484f58;margin-top:2px">decoded=${data.samples_decoded}  total=${data.total_samples}  pretrig=${data.pretrig_samples}  sr=${data.sample_rate}  geoRange=${geoRange.toFixed(3)}</div>`;
+
+  cont.innerHTML = html;
+  dbg.style.display = 'block';
+}
+
+function updateDebugPanel(data) {
+  _fillDebugPanel(data, document.getElementById('debug-panel'), document.getElementById('debug-content'));
+}
+
 // ── DB tabs ────────────────────────────────────────────────────────────────────
 let histLoaded   = false;
 let unitsLoaded  = false;
@@ -1745,6 +1837,7 @@ async function loadHistory() {
     const pvs = ev.peak_vector_sum;
     const maxPPV = Math.max(ev.tran_ppv ?? 0, ev.vert_ppv ?? 0, ev.long_ppv ?? 0);
     tr.innerHTML = `
+      <td><button class="wf-btn" onclick="openDbWaveformModal('${ev.id}')" title="View waveform">〜</button></td>
       <td>${_fmtTs(ev.timestamp)}</td>
       <td class="td-key">${ev.serial ?? '—'}</td>
       <td class="${_ppvClass(ev.tran_ppv)}">${_ppvFmt(ev.tran_ppv)}</td>
@@ -1919,9 +2012,86 @@ async function loadSessions() {
   }
 }
 
+// ── DB waveform modal ─────────────────────────────────────────────────────────
+let modalCharts = {};
+
+async function openDbWaveformModal(id) {
+  const modal    = document.getElementById('wf-modal');
+  const titleEl  = document.getElementById('wf-modal-title');
+  const chartsEl = document.getElementById('wf-modal-charts');
+  const emptyEl  = document.getElementById('wf-modal-empty');
+  const peaksEl  = document.getElementById('wf-modal-peaks');
+  const debugEl  = document.getElementById('wf-modal-debug');
+
+  // Show modal in loading state
+  titleEl.textContent = 'Loading…';
+  peaksEl.classList.remove('visible');
+  if (debugEl) debugEl.style.display = 'none';
+  chartsEl.style.display = 'none';
+  chartsEl.innerHTML = '';
+  emptyEl.style.display = 'flex';
+  emptyEl.querySelector('p').textContent = 'Loading waveform…';
+  modal.style.display = 'flex';
+
+  let data;
+  try {
+    const r = await fetch(`${api()}/db/events/${encodeURIComponent(id)}/waveform`);
+    if (!r.ok) { const e = await r.json().catch(()=>({})); throw new Error(e.detail || r.statusText); }
+    data = await r.json();
+  } catch(e) {
+    emptyEl.querySelector('p').textContent = `Error: ${e.message}`;
+    return;
+  }
+
+  // Normalize old blob peak_values keys (pre-fix ACH blobs used tran/vert/long without _in_s)
+  if (data.peak_values) {
+    const pv = data.peak_values;
+    if (pv.tran_in_s == null && pv.tran != null) pv.tran_in_s = pv.tran;
+    if (pv.vert_in_s == null && pv.vert != null) pv.vert_in_s = pv.vert;
+    if (pv.long_in_s == null && pv.long != null) pv.long_in_s = pv.long;
+  }
+
+  // Header — DB blobs have timestamp as ISO string; live device returns {display:...}
+  const sr      = data.sample_rate || 1024;
+  const decoded = data.samples_decoded || 0;
+  const total   = data.total_samples || decoded;
+  const pretrig = data.pretrig_samples || 0;
+  let tsStr = '';
+  if (data.timestamp) {
+    const tsDisplay = typeof data.timestamp === 'object'
+      ? (data.timestamp.display || String(data.timestamp))
+      : new Date(data.timestamp).toLocaleString();
+    tsStr = `<strong style="color:var(--text)">${tsDisplay}</strong>  `;
+  }
+  titleEl.innerHTML = `${tsStr}<span style="color:var(--text-dim)">${data.record_type || '?'} · ${sr} sps · ${decoded.toLocaleString()} / ${total.toLocaleString()} samples · pretrig ${pretrig} · ${data.rectime_seconds ?? '?'} s</span>`;
+
+  // Peaks bar
+  const pv = data.peak_values || {};
+  const micDbl = pv.micl_psi != null && pv.micl_psi > 0 ? 20 * Math.log10(pv.micl_psi / DBL_REF) : null;
+  document.getElementById('wf-mpk-tran').textContent = pv.tran_in_s != null ? `${pv.tran_in_s.toFixed(5)} in/s` : '—';
+  document.getElementById('wf-mpk-vert').textContent = pv.vert_in_s != null ? `${pv.vert_in_s.toFixed(5)} in/s` : '—';
+  document.getElementById('wf-mpk-long').textContent = pv.long_in_s != null ? `${pv.long_in_s.toFixed(5)} in/s` : '—';
+  document.getElementById('wf-mpk-mic').textContent  = micDbl != null ? `${micDbl.toFixed(1)} dBL` : '—';
+  document.getElementById('wf-mpk-pvs').textContent  = pv.peak_vector_sum != null ? `${pv.peak_vector_sum.toFixed(5)} in/s` : '—';
+  peaksEl.classList.add('visible');
+
+  _buildWaveformCharts(data, chartsEl, emptyEl, modalCharts);
+  _fillDebugPanel(data, debugEl, document.getElementById('wf-modal-debug-content'));
+}
+
+function closeWfModal() {
+  const modal = document.getElementById('wf-modal');
+  if (!modal || modal.style.display === 'none') return;
+  modal.style.display = 'none';
+  // Destroy chart instances to free canvas memory
+  Object.values(modalCharts).forEach(c => c.destroy());
+  for (const k in modalCharts) delete modalCharts[k];
+}
+
 // ── Keyboard shortcuts ─────────────────────────────────────────────────────────
 document.addEventListener('keydown', e => {
   if (e.target.tagName === 'INPUT' || e.target.tagName === 'SELECT') return;
+  if (e.key === 'Escape') { closeWfModal(); return; }
   if (e.key === 'ArrowLeft')  { stepEvent(-1); e.preventDefault(); }
   if (e.key === 'ArrowRight') { stepEvent(+1); e.preventDefault(); }
 });
@@ -1935,5 +2105,25 @@ document.getElementById('api-base').value = window.location.origin;
   document.getElementById(id)?.addEventListener('keydown', e => { if (e.key === 'Enter') connectUnit(); });
 });
 </script>
-</body>
+
-</html>
+<!-- ── Waveform Modal (DB history view) ──────────────────────────────────────
+     Opened by openDbWaveformModal(id).  Click outside or press Esc to close. -->
+<div id="wf-modal"
+     style="display:none; position:fixed; inset:0; z-index:1000;
+            background:rgba(1,4,9,0.88); align-items:flex-start;
+            justify-content:center; padding:24px; overflow:auto;"
+     onclick="if(event.target===this)closeWfModal()">
+  <div style="background:var(--surface); border:1px solid var(--border);
+              border-radius:8px; width:100%; max-width:1100px;
+              display:flex; flex-direction:column; max-height:calc(100vh - 48px);">
+
+    <!-- Header row -->
+    <div style="display:flex; align-items:center; padding:10px 16px;
+                border-bottom:1px solid var(--border); flex-shrink:0; gap:10px;">
+      <div id="wf-modal-title"
+           style="flex:1; font-size:12px; color:var(--text-dim); font-family:monospace; overflow:hidden; white-space:nowrap; text-overflow:ellipsis;">
+        —
+      </div>
+      <button onclick="closeWfModal()"
+              style="background:none; border:none; color:var(--text-dim); cursor:pointer;
+                     font-si

sfm/waveform_viewer.html

@@ -175,6 +175,27 @@
     }
     #connect-btn:hover { background: #2ea043; }
     #connect-btn:disabled { background: #21262d; color: #484f58; }
+
+    #debug-panel {
+      display: none;
+      background: #0d1117;
+      border-bottom: 1px solid #21262d;
+      padding: 6px 20px;
+      font-family: monospace;
+      font-size: 11px;
+      color: #6e7681;
+      line-height: 1.7;
+    }
+    #debug-panel.visible { display: block; }
+    #debug-panel .dp-row { display: flex; gap: 24px; flex-wrap: wrap; }
+    #debug-panel .dp-ch  { color: #8b949e; }
+    #debug-panel .dp-ch span { color: #c9d1d9; }
+    #debug-panel .dp-warn { color: #e3b341; }
+    #debug-toggle {
+      background: none; border: none; color: #484f58; font-size: 11px;
+      cursor: pointer; padding: 0; float: right; text-decoration: underline;
+    }
+    #debug-toggle:hover { color: #8b949e; }
   </style>
 </head>
 <body>
@@ -193,6 +214,12 @@
   </div>
   <button id="connect-btn" onclick="connectUnit()">Connect</button>
   <button id="load-btn" onclick="loadWaveform()" disabled>Load Waveform</button>
+  <label style="display:flex;align-items:center;gap:4px;color:#8b949e;font-size:12px;cursor:pointer"
+         title="Re-download from device, bypassing server cache. Check this then click Load Waveform (or checking it will auto-reload if a waveform is already shown).">
+    <input type="checkbox" id="force-reload" style="accent-color:#1f6feb"
+           onchange="if(this.checked && lastData !== null) loadWaveform()" />
+    Force&nbsp;reload
+  </label>
   <button id="prev-btn" onclick="stepEvent(-1)" disabled>◀ Prev</button>
   <button id="next-btn" onclick="stepEvent(+1)" disabled>Next ▶</button>
 </header>
@@ -219,6 +246,10 @@
 </div>
 
 <div id="status-bar">Ready — enter device host and click Connect.</div>
+<div id="debug-panel">
+  <button id="debug-toggle" onclick="document.getElementById('debug-panel').classList.remove('visible')">hide</button>
+  <div id="debug-content"></div>
+</div>
 
 <div id="empty-state">
   <svg width="48" height="48" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5">
@@ -244,6 +275,46 @@
   let eventList = [];        // populated from /device/events after connect
   let currentEventIndex = 0;
 
+  // ── DB mode: opened via ?db_id=<uuid>&api_base=<url> from History tab ────────
+  const _urlParams  = new URLSearchParams(window.location.search);
+  const _dbId       = _urlParams.get('db_id');
+  const _dbApiBase  = (_urlParams.get('api_base') || '').replace(/\/$/, '');
+
+  async function _loadFromDb() {
+    const apiBase = _dbApiBase || document.getElementById('api-base').value.replace(/\/$/, '');
+    setStatus('Loading waveform from database…', 'loading');
+    document.getElementById('unit-bar').style.display = 'none';
+    // Hide live-device controls — not relevant in DB mode
+    document.querySelector('header .conn-group').style.display = 'none';
+
+    const url = `${apiBase}/db/events/${encodeURIComponent(_dbId)}/waveform`;
+    let data;
+    try {
+      const resp = await fetch(url);
+      if (!resp.ok) {
+        const err = await resp.json().catch(() => ({ detail: resp.statusText }));
+        throw new Error(err.detail || resp.statusText);
+      }
+      data = await resp.json();
+    } catch (e) {
+      setStatus(`Error: ${e.message}`, 'error');
+      return;
+    }
+    lastData = data;
+    renderWaveform(data);
+  }
+
+  // Auto-load when opened with db_id param
+  window.addEventListener('DOMContentLoaded', () => {
+    if (_dbId) {
+      // Pre-fill api-base if provided
+      if (_dbApiBase) {
+        document.getElementById('api-base').value = _dbApiBase;
+      }
+      _loadFromDb();
+    }
+  });
+
   function setStatus(msg, cls = '') {
     const bar = document.getElementById('status-bar');
     bar.textContent = msg;
@@ -364,7 +435,8 @@
     btn.disabled = true;
     setStatus('Fetching waveform…', 'loading');
 
-    const url = `${apiBase}/device/event/${evIndex}/waveform?host=${encodeURIComponent(devHost)}&tcp_port=${tcpPort}`;
+    const force = document.getElementById('force-reload')?.checked ? '&force=true' : '';
+    const url = `${apiBase}/device/event/${evIndex}/waveform?host=${encodeURIComponent(devHost)}&tcp_port=${tcpPort}${force}`;
 
     let data;
     try {
@@ -404,8 +476,11 @@
     bar.innerHTML = '';
     bar.className = 'ok';
     const ts = data.timestamp;
-    if (ts) {
+    const tsDisplay = ts
-      bar.textContent = `Event #${data.index}  —  ${ts.display}    `;
+      ? (typeof ts === 'string' ? ts : (ts.display ?? JSON.stringify(ts)))
+      : null;
+    if (tsDisplay) {
+      bar.textContent = `Event #${data.index}  —  ${tsDisplay}    `;
     } else {
       bar.textContent = `Event #${data.index}    `;
     }
@@ -413,7 +488,14 @@
     appendMeta('sr', `${sr} sps`);
     appendMeta('samples', `${decoded.toLocaleString()} / ${total.toLocaleString()}`);
     appendMeta('pretrig', pretrig);
-    appendMeta('rectime', `${data.rectime_seconds ?? '?'}s`);
+    // rectime_seconds is computed from (total_samples - pretrig_samples) / sr in
+    // _decode_a5_waveform.  Also show the compliance config record_time for reference.
+    const cfgRt = unitInfo?.compliance_config?.record_time;
+    const strtRt = data.rectime_seconds;
+    const rtStr = (strtRt !== null && strtRt !== undefined)
+      ? `${strtRt}s (stored)` + (cfgRt !== null && cfgRt !== undefined ? ` / ${cfgRt}s (cfg)` : '')
+      : (cfgRt !== null && cfgRt !== undefined ? `${cfgRt}s (cfg)` : '?');
+    appendMeta('rectime', rtStr);
 
     // No waveform data — show a clear reason instead of empty charts
     if (decoded === 0) {
@@ -423,14 +505,20 @@
           ? 'Waveform decode returned no samples — check server logs'
           : `Record type "${recType}" — waveform decode not yet supported for this mode`;
       document.getElementById('charts').style.display = 'none';
+      document.getElementById('debug-panel').classList.remove('visible');
       Object.values(charts).forEach(c => c.destroy());
       charts = {};
       return;
     }
 
-    // Build time axis (ms)
+    // Clip to total_samples to exclude zero-padding the device appends beyond
-    const times = Array.from({ length: decoded }, (_, i) =>
+    // the configured record window.  total = pretrig + post_trig (e.g. 256+3072=3328).
-      ((i - pretrig) / sr * 1000).toFixed(2)
+    // decoded may be larger (e.g. 4495) due to trailing zero-padded bulk-stream frames.
+    const displayCount = (total > 0 && total < decoded) ? total : decoded;
+
+    // Build time axis in seconds (matching Blastware event report layout).
+    const times = Array.from({ length: displayCount }, (_, i) =>
+      ((i - pretrig) / sr).toFixed(3)
     );
 
     // Show charts area
@@ -447,6 +535,15 @@
     const micPeakPsi = data.peak_values?.micl_psi ?? null;
     const DBL_REF_PSI = 2.9e-9; // 20 µPa in psi
 
+    // 0C record peak values (device-computed, authoritative) per channel.
+    // Keys: live-device endpoint uses tran_in_s/vert_in_s/long_in_s;
+    // DB blobs created before 2026-04-14 used tran/vert/long — fall back for compat.
+    const peakValues0C = {
+      Tran: data.peak_values?.tran_in_s ?? data.peak_values?.tran ?? null,
+      Vert: data.peak_values?.vert_in_s ?? data.peak_values?.vert ?? null,
+      Long: data.peak_values?.long_in_s ?? data.peak_values?.long ?? null,
+    };
+
     for (const [ch, color] of Object.entries(CHANNEL_COLORS)) {
       const samples = channels[ch];
       if (!samples || samples.length === 0) continue;
@@ -455,22 +552,38 @@
       const isGeo = ch !== 'Mic';
       let plotSamples, peakLabel, yUnit, tooltipFmt, tickFmt;
 
+      // Clip channel samples to displayCount (same as time axis)
+      const clippedSamples = samples.length > displayCount
+        ? samples.slice(0, displayCount)
+        : samples;
+
+      // peak0C declared here (function scope) so it is visible in the Chart.js
+      // config block below (which lives outside the if(isGeo) block).
+      let peak0C = null;
+
       if (isGeo) {
         // Geo channels: counts × (range / 32767) → in/s
+        // Scale factor for the waveform shape (may need calibration per unit)
         const scale = geoRange / 32767;
-        plotSamples = samples.map(c => c * scale);
+        plotSamples = clippedSamples.map(c => c * scale);
-        const peakIns = Math.max(...plotSamples.map(Math.abs));
+
+        // Use the device-computed 0C record peak for the label (authoritative).
+        // The raw-sample-computed peak can be inflated by frame-boundary artifacts.
+        peak0C = peakValues0C[ch];
+        const peakIns = (peak0C !== null && peak0C !== undefined)
+          ? peak0C
+          : Math.max(...plotSamples.map(Math.abs));
         peakLabel  = `${peakIns.toFixed(5)} in/s`;
         yUnit      = 'in/s';
         tooltipFmt = v => `${ch}: ${v.toFixed(5)} in/s`;
         tickFmt    = v => v.toFixed(4);
       } else {
         // Mic: derive psi/count scale from the 0C peak value, display as psi; show dBL in header
-        const peakCounts = Math.max(...samples.map(Math.abs));
+        const peakCounts = Math.max(...clippedSamples.map(Math.abs));
         const micScale   = (micPeakPsi !== null && peakCounts > 0)
           ? Math.abs(micPeakPsi) / peakCounts
           : 1.0;
-        plotSamples = samples.map(c => c * micScale);
+        plotSamples = clippedSamples.map(c => c * micScale);
         const peakPsi = Math.max(...plotSamples.map(Math.abs));
         const peakDbl = peakPsi > 0 ? 20 * Math.log10(peakPsi / DBL_REF_PSI) : -Infinity;
         peakLabel  = `${peakDbl.toFixed(1)} dBL  (${peakPsi.toExponential(3)} psi)`;
@@ -504,7 +617,9 @@
         renderData  = plotSamples.filter((_, i) => i % step === 0);
       }
 
-      const chart = new Chart(canvas, {
+      let chart;
+      try {
+        chart = new Chart(canvas, {
           type: 'line',
           data: {
             labels: renderTimes,
@@ -526,7 +641,7 @@
                 mode: 'index',
                 intersect: false,
                 callbacks: {
-                title: items => `t = ${items[0].label} ms`,
+                  title: items => `t = ${items[0].label} s`,
                   label: item => tooltipFmt(item.raw),
                 },
               },
@@ -538,11 +653,21 @@
                   color: '#484f58',
                   maxTicksLimit: 10,
                   maxRotation: 0,
-                callback: (val, i) => renderTimes[i] + ' ms',
+                  callback: (val, i) => renderTimes[i] + ' s',
                 },
                 grid: { color: '#21262d' },
               },
               y: {
+                // Clamp geo-channel y-axis to ±(0C peak × 1.4) so near-saturation
+                // decode artifacts (which inflate autoscale to full range) don't
+                // squash the actual blast signal into an invisible flat line.
+                // The 0C peak value is authoritative for the true signal amplitude.
+                // Guard: only apply if peak0C is a valid finite positive number.
+                ...(isGeo && peak0C !== null && peak0C !== undefined
+                      && isFinite(peak0C) && peak0C > 0 ? {
+                  min: -(peak0C * 1.4),
+                  max:  (peak0C * 1.4),
+                } : {}),
                 ticks: {
                   color: '#484f58',
                   maxTicksLimit: 5,
@@ -566,7 +691,7 @@
               const xAxis = chart.scales.x;
               const yAxis = chart.scales.y;
 
-            // Find index of t=0
+              // Find index of the trigger point (t ≥ 0.000 s)
               const zeroIdx = renderTimes.findIndex(t => parseFloat(t) >= 0);
               if (zeroIdx < 0) return;
 
@@ -583,9 +708,48 @@
             },
           }],
         });
-
+      } catch (err) {
-      charts[ch] = chart;
+        console.error(`Chart.js error for channel ${ch}:`, err);
+        canvasWrap.innerHTML = `<p style="color:#f85149;padding:8px;font-size:11px;">Chart error: ${err.message}</p>`;
       }
+
+      if (chart) charts[ch] = chart;
+    }
+
+    // ── Debug panel: raw ADC counts + decode diagnostics ────────────────────
+    // Shows the first 8 decoded ADC counts per channel and whether peak values
+    // came from the 0C record (authoritative) or from Math.max fallback.
+    // Useful for diagnosing channel misalignment without touching server logs.
+    const dbg = document.getElementById('debug-panel');
+    const dbgContent = document.getElementById('debug-content');
+    const geoChans = ['Tran', 'Vert', 'Long'];
+    const rawChans = channels;
+    const scale = geoRange / 32767;
+
+    let dbgHtml = '<div class="dp-row">';
+
+    // per-channel first-8 raw counts
+    for (const ch of [...geoChans, 'Mic']) {
+      const raw = (rawChans[ch] || []).slice(0, 8);
+      if (raw.length === 0) continue;
+      const maxAbs = Math.max(...raw.map(Math.abs));
+      const p0c = peakValues0C?.[ch] ?? null;
+      const src = (ch !== 'Mic' && p0c !== null) ? `0C=${p0c.toFixed(4)}` : `Math.max=${(maxAbs*scale).toFixed(4)}`;
+      dbgHtml += `<div class="dp-ch">${ch} raw[0:8]: <span>${raw.join(', ')}</span>  peak src: <span>${src}</span></div>`;
+    }
+    dbgHtml += '</div>';
+
+    // warn if peak0C was null for any geo channel
+    const nullPeaks = geoChans.filter(ch => (peakValues0C?.[ch] ?? null) === null);
+    if (nullPeaks.length > 0) {
+      dbgHtml += `<div class="dp-warn">⚠ peak0C null for: ${nullPeaks.join(', ')} — using Math.max fallback (check Force reload + Load Waveform)</div>`;
+    }
+
+    // summary line
+    dbgHtml += `<div>decoded=${data.samples_decoded}  total=${data.total_samples}  pretrig=${data.pretrig_samples}  sr=${data.sample_rate}  geoRange=${geoRange}</div>`;
+
+    dbgContent.innerHTML = dbgHtml;
+    dbg.classList.add('visible');
   }
 
   // Auto-detect API base from wherever this page was served from