debug(protocol): event-N probe is now at counter = start_offset instead of start_offset + 0x46

minimateplus/protocol.py

@@ -608,13 +608,23 @@ class MiniMateProtocol:
             probe_params  = bulk_waveform_params(key4, 0, is_probe=True)
             log.debug("5A probe (event-1)  key=%s  counter=0x0000", key4.hex())
         else:
-            # Continuation events: first 5A request lands at start+0x0046,
-            # acting as both probe and first sample chunk.  Confirmed from
-            # 5-1-26 "copy 2nd address event" capture.
-            probe_counter = start_offset + 0x0046
+            # Continuation events: first 5A request lands at counter = key[2:4]
+            # (i.e. the address of the off=0x46 WAVEHDR record returned by 1F).
+            # The probe response carries STRT at byte 17 with end_offset.
+            #
+            # Confirmed 2026-05-04 from 5-1-26 "copy 2nd address" capture
+            # (BW probes counter=0x2238 with key=01112238, STRT@17 end=0x417E)
+            # and 5-4-26 BW captures (2-sec event probes counter=0x2238).
+            #
+            # The earlier "+0x46" formula in the doc came from calling
+            # start_key the BOUNDARY (off=0x2C) key, but the iteration walk
+            # uses 1F's off=0x46 key as cur_key, which already incorporates
+            # the +0x46 offset relative to the boundary.  Adding it again
+            # caused the probe to overshoot, miss STRT, and run uncapped.
+            probe_counter = start_offset
             probe_params  = bulk_waveform_params(key4, probe_counter)
             log.debug(
-                "5A probe (event-N)  key=%s  counter=0x%04X (start+0x46)",
+                "5A probe (event-N)  key=%s  counter=0x%04X",
                 key4.hex(), probe_counter,
             )