improved the logtool, but not quite there yet?

logtool/debug-notes.md

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+# Logtool Debug Notes — 16 MAR 2026
+
+## Problem
+`storage-16MAR2026-1728.bin` not parsing correctly.
+
+## Root Cause (SOLVED)
+Two issues in `parser.py`:
+
+### 1. Unrecognized file format
+The file format is `[4B tail BE][4B head BE][raw log data]` — no JSON header.
+- `head - tail == file_size - 8` (the raw log data is exactly the flash region from tail to head)
+- The old HTTP format was: `[4B json_len BE][json][4B tail BE][4B head BE][raw log data]`
+- The parser's autodetect only recognized the old HTTP format (and required json_len < 8192)
+- **Fix:** Added detection for bare tail+head format in `autodetect_and_parse()`
+
+### 2. Type-first vs type-last detection failure
+The log entries use **type-first** format: `[len][type][payload]`
+But `_try_detect_type_first()` returned False because:
+- First entry had type=0x00 at both positions (ambiguous)
+- Timestamp was near-zero (RTC not yet set), so timestamp sanity check failed
+- Function gave up after only 1 entry (`break` at end of loop)
+- **Fix:** Loop over multiple entries (up to 200), added voltage sanity check (0.5-60V)
+
+## Verification
+- 54,831 entries parsed successfully
+- FSM states: IDLE (51169), JACK_UP (1078), DRIVE (994), etc.
+- Voltages: 3.3V–13.3V (reasonable for 3S LiPo system)
+- Timestamps: Jan 13 – Feb 6, 2026 (after RTC set)
+- Old HTTP-format .bin files still parse correctly