fix(protocol): enhance extra chunk fetching logic to ensure footer detection

minimateplus/protocol.py

@@ -652,8 +652,14 @@ class MiniMateProtocol:
                 # and primes the device to return a valid footer in the termination
                 # response.  Without it, termination returns an empty ack with no
                 # footer bytes (confirmed 2026-04-23 from HxD comparison).
-                log.debug("5A A5[%d] metadata found — fetching %d more chunk(s) then stopping",
+                # Download extra chunks until we find the footer chunk (contains
-                          chunk_num, extra_chunks_after_metadata)
+                # 0x0e 0x08 near its end) or hit the extra_chunks_after_metadata
+                # cap.  The footer bytes are embedded in the last meaningful data
+                # chunk, NOT in the termination response.  For short events (1-sec)
+                # the footer is in extra chunk 1.  For longer events it is in a
+                # later chunk.  Confirmed 2026-04-23 from BW file comparison.
+                log.debug("5A A5[%d] metadata found — fetching extra chunks until footer found",
+                          chunk_num)
                 for _extra_n in range(extra_chunks_after_metadata):
                     chunk_num += 1
                     counter = chunk_num * _BULK_COUNTER_STEP
@@ -661,13 +667,20 @@ class MiniMateProtocol:
                     self._send(build_5a_frame(_BULK_CHUNK_OFFSET, params))
                     try:
                         extra = self._recv_one(expected_sub=rsp_sub, timeout=10.0)
-                        log.debug("5A A5[%d] extra chunk page_key=0x%04X data_len=%d",
+                        log.debug("5A A5[%d] extra chunk page_key=0x%04X data_len=%d has_footer=%s",
-                                  chunk_num, extra.page_key, len(extra.data))
+                                  chunk_num, extra.page_key, len(extra.data),
+                                  b'\x0e\x08' in extra.data[-50:])
                         if extra.page_key == 0x0000:
                             if include_terminator:
                                 frames_data.append(extra)
                             return frames_data
                         frames_data.append(extra)
+                        # Stop as soon as we find the footer marker in the tail
+                        # of this chunk — the body is complete.
+                        if b'\x0e\x08' in extra.data[-50:]:
+                            log.debug("5A A5[%d] footer marker found — stopping extra chunks",
+                                      chunk_num)
+                            break
                     except TimeoutError:
                         log.debug("5A extra chunk %d timed out — end of stream", _extra_n + 1)
                         break

sfm/server.py

@@ -885,17 +885,17 @@ def device_event_blastware_file(
         def _do():
             with _build_client(port, baud, host, tcp_port, timeout=120.0) as client:
                 info = client.connect()
-                # Calculate extra ADC chunks to download after finding "Project:".
+                # Download extra chunks after "Project:" until the footer marker
-                # BW downloads ~2 extra chunks per second of record time.
+                # 0x0e 0x08 is detected in a chunk tail.  The cap prevents
-                # Without enough extra chunks the termination response contains no
+                # accidentally downloading into post-event silence.
-                # footer bytes and Blastware rejects the file.
+                # Cap = rectime * 4 + 4 covers up to ~10 sec events safely.
                 rectime = 1.0
                 try:
                     rectime = float(info.compliance_config.record_time or 1.0)
                 except (AttributeError, TypeError, ValueError):
                     pass
-                extra_chunks = max(1, int(rectime))
+                extra_chunks = max(4, int(rectime * 4) + 4)
-                log.info("blastware_file: rectime=%.1fs → extra_chunks=%d", rectime, extra_chunks)
+                log.info("blastware_file: rectime=%.1fs → extra_chunks_cap=%d", rectime, extra_chunks)
                 events = client.get_events(
                     full_waveform=False,
                     stop_after_index=index,