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09 — Open questions

What is still unknown about the pedal, ordered by how much it matters for an editor. Each item says how it could be answered. Most need a capture of the official app (07) or an experiment on the pedal. If you find an answer, please open an issue or a pull request that updates this page.

High value

  1. Preset unknown bytes: offset 8 (0x62), 79–81, 82 (6), 90–93. Toggle things in the app that aren’t covered yet (chain reordering, tempo/BPM per preset, scenes if any) and diff 0x0C reads.
  2. Host→pedal CCs not yet captured: loop mode 0x4A and tuner control. (Drum pattern 0x40 and loop levels 0x42/0x43 are confirmed, see 02.)
  3. Writing the edit buffer (0x0C dir 1): does it exist? The app only uses live CCs and the 0x0B save.
  4. Preset and settings writes on hardware: the library’s writes match the official app byte for byte, but haven’t been run on a pedal from this code yet.
  5. IR slot 4-byte field (0x09 record bytes 0–3): 01 00 00 00 in all eleven captured imports (ten slots, different files and names), so probably a constant or a “slot in use” flag.

Medium

  1. Settings unknown bytes 0, 2 (30), 3 (10), 7–8 (50, 50), 11 (60), 12 (180). Candidates: energy-saving mode, USB audio routing (Normal / LoopBack / Reamp / Dry-Wet per static strings), display, MIDI channel.
  2. Value → unit curves: CAB LOW/HIGH CUT raw → Hz, EQ raw → dB, tuner cents scale, delay TIME → ms, Hall pre-delay. Read the app’s displayed value at several raw values, or find the tables in the snapshot (the static analysis found log-spaced “20…1000” and “5000…20000” string tables).
  3. Current-state 0x15 fields (50 01 …).
  4. Unsolicited F0 00 21 7A 10 F7, seen twice mid-session.
  5. Delta CC dumps: confirm that the CC burst after a program change only contains changed values, by switching between two presets that differ in one parameter.
  6. LSTM and ConvNet NAM models: the app’s NAM core supports ConvNet too; the library converts WaveNet models only.

Low / out of scope

  1. Bluetooth pacing: 15 ms between messages works; the fastest safe pacing is unknown.
  2. The official app’s import/export/backup file formats (.bin, the preset import list dialog). Not captured.
  3. Firmware DFU over USB HID (separate updater). Not explored here.
  4. The legacy “Syx/Cherub” header 43 58 70 7E seen in static analysis: never observed from this pedal.

Resolved

  • NAM → device conversion: recovered and implemented (open_stomp::nam, 05). An Ampeg SVT model converted by the official algorithm and by ours sounds identical on the pedal.
  • IR transform: resampled first channel, first 2048 samples reversed, gain centring the 398 Hz–3 kHz response on 0 dB. ir::convert matches eleven captured imports. The pedal plays only the first 384 taps (05).
  • 0x12 set-name first byte: the active preset (P69 = 0x44 was selected just before the captured save).
  • BLE-MIDI: the same messages as over USB, NAM and IR uploads included (01).