diff --git a/minimateplus/client.py b/minimateplus/client.py
index bb72858..bcae5de 100644
--- a/minimateplus/client.py
+++ b/minimateplus/client.py
@@ -838,7 +838,9 @@ def _extract_record_type(data: bytes) -> Optional[str]:
     code = data[1]
     if code == 0x10:
         return "Waveform"
-    # TODO: add histogram sub_code once a histogram event is captured with debug=true
+    # Unknown code — log it so we can identify histogram/noise sub_codes from real captures
+    log.warning("_extract_record_type: unknown sub_code=0x%02X — returning raw string", code)
+    return f"Unknown(0x{code:02X})"
     return None
 
 
diff --git a/sfm/server.py b/sfm/server.py
index c2f7240..fc87f8e 100644
--- a/sfm/server.py
+++ b/sfm/server.py
@@ -183,21 +183,23 @@ def _build_client(
     baud: int,
     host: Optional[str],
     tcp_port: int,
+    timeout: float = 30.0,
 ) -> MiniMateClient:
     """
     Return a MiniMateClient configured for either serial or TCP transport.
 
     TCP takes priority if *host* is supplied; otherwise *port* (serial) is used.
     Raises HTTPException(422) if neither is provided.
+
+    Use timeout=120.0 (or higher) for endpoints that perform a full 5A waveform
+    download — a 70-second event at 1024 sps takes 2-3 minutes to transfer over
+    cellular and each individual recv must complete within the timeout window.
     """
     if host:
-        # TCP / modem / ACH path — use a longer timeout to survive cold boots
-        # (unit takes 5-15s to wake from RS-232 line assertion over cellular)
         transport = TcpTransport(host, port=tcp_port)
-        log.debug("TCP transport: %s:%d", host, tcp_port)
-        return MiniMateClient(transport=transport, timeout=30.0)
+        log.debug("TCP transport: %s:%d  timeout=%.0fs", host, tcp_port, timeout)
+        return MiniMateClient(transport=transport, timeout=timeout)
     elif port:
-        # Direct serial path
         log.debug("Serial transport: %s baud=%d", port, baud)
         return MiniMateClient(port, baud)
     else:
@@ -425,7 +427,7 @@ def device_event_waveform(
 
     try:
         def _do():
-            with _build_client(port, baud, host, tcp_port) as client:
+            with _build_client(port, baud, host, tcp_port, timeout=120.0) as client:
                 info = client.connect()
                 # full_waveform=True fetches the complete 5A stream inside the
                 # 1E→0A→0C→5A→1F loop.  Issuing a second 5A after 1F times out.
@@ -458,12 +460,14 @@ def device_event_waveform(
 
     return {
         "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,
         "samples_decoded": samples_decoded,
         "sample_rate":     sample_rate,
+        "peak_values":     _serialise_peak_values(ev.peak_values),
         "channels":        raw,
     }
 
diff --git a/sfm/waveform_viewer.html b/sfm/waveform_viewer.html
index 5ec560c..d5d6f5f 100644
--- a/sfm/waveform_viewer.html
+++ b/sfm/waveform_viewer.html
@@ -374,13 +374,7 @@
     const decoded   = data.samples_decoded || 0;
     const total     = data.total_samples   || decoded;
     const channels  = data.channels || {};
-
-    // Build time axis (ms)
-    const times = Array.from({ length: decoded }, (_, i) =>
-      ((i - pretrig) / sr * 1000).toFixed(2)
-    );
-
-    const triggerMs = 0;  // t=0 is trigger by construction
+    const recType   = data.record_type || 'Unknown';
 
     // Status bar
     const bar = document.getElementById('status-bar');
@@ -392,11 +386,30 @@
     } else {
       bar.textContent = `Event #${data.index}    `;
     }
+    appendMeta('type', recType);
     appendMeta('sr', `${sr} sps`);
     appendMeta('samples', `${decoded.toLocaleString()} / ${total.toLocaleString()}`);
     appendMeta('pretrig', pretrig);
     appendMeta('rectime', `${data.rectime_seconds ?? '?'}s`);
 
+    // No waveform data — show a clear reason instead of empty charts
+    if (decoded === 0) {
+      document.getElementById('empty-state').style.display = 'flex';
+      document.getElementById('empty-state').querySelector('p').textContent =
+        recType === 'Waveform'
+          ? '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';
+      Object.values(charts).forEach(c => c.destroy());
+      charts = {};
+      return;
+    }
+
+    // Build time axis (ms)
+    const times = Array.from({ length: decoded }, (_, i) =>
+      ((i - pretrig) / sr * 1000).toFixed(2)
+    );
+
     // Show charts area
     document.getElementById('empty-state').style.display = 'none';
     const chartsDiv = document.getElementById('charts');