diff --git a/sfm/server.py b/sfm/server.py
index 5d57c49..97dd7b2 100644
--- a/sfm/server.py
+++ b/sfm/server.py
@@ -873,8 +873,8 @@ def device_event_blastware_file(
                         triggered events; histogram requires recording_mode
                         to be populated from compliance config)
 
-    Performs: POLL startup → get_events(full_waveform=False, stop_after_index=index)
-    → write_blastware_file() → FileResponse.
+    Performs: POLL startup → get_events(full_waveform=False, extra_chunks=1,
+    stop_after_index=index) → write_blastware_file() → FileResponse.
     """
     log.info(
         "GET /device/event/%d/blastware_file  port=%s host=%s",
@@ -885,17 +885,21 @@ def device_event_blastware_file(
         def _do():
             with _build_client(port, baud, host, tcp_port, timeout=120.0) as client:
                 info = client.connect()
-                # Use full_waveform=True (stop_after_metadata=False) so the device
-                # streams until it naturally signals end-of-stream (1-raw-byte signal).
-                # BW does the same — the ACH download and manual pull both let the device
-                # determine when to stop.  The termination response at that point contains
-                # the correct 0e 08 footer with monitoring timestamps.
-                # For Continuous/Single-Shot events, end-of-stream comes after the real
-                # ADC data (not after 35+ silence chunks as in Histogram+Continuous mode).
-                # max_chunks=32 is a safety cap; natural end-of-stream stops much earlier.
+                # Use stop_after_metadata=True (full_waveform=False) with 1 extra
+                # chunk after "Project:".  For any record time, the pre-metadata
+                # section of the 5A stream naturally carries proportionally more
+                # ADC data for longer events — so "1 extra chunk" produces the
+                # correct body length regardless of record time.
+                #
+                # full_waveform=True (natural end-of-stream) downloads ALL chunks
+                # including post-event silence (35+ chunks for a 9-sec event at
+                # 1024 sps) — this produces 24KB+ files that Blastware rejects.
+                # Confirmed from file size comparison: BW 1-sec=4400B, BW 3-sec=8114B,
+                # per-second delta 1857 bytes — matches pre-metadata frame scaling.
                 events = client.get_events(
-                    full_waveform=True,
+                    full_waveform=False,
                     stop_after_index=index,
+                    extra_chunks_after_metadata=1,
                 )
                 matching = [ev for ev in events if ev.index == index]
                 return matching[0] if matching else None, info