Boot Trace
A probe for finding where a boot hangs. It sends one MIDI note on MIDI OUT at each stage of the boot, so a hang on the unit names its stage: the last note a MIDI monitor receives is the last stage that ran.
Access
No menu and no screen. Connect a MIDI monitor to MIDI OUT and boot. Not in
an official remix; build the test remix remix-switch-trace. It was built
for REMIX SWITCH's hardware bring-up and has run on a MKII (29 Sep 2026).
Operation
Each note is Note On, channel 1, velocity 127 unless noted:
| Note | Stage |
|---|---|
| 1 | the OS entry ran (sent by REMIX SWITCH's chainloader when it is in the image) |
| 2 | the DSP upload starts |
| 3 | the DSP upload returned |
| 4 | the panel link's init |
| 5 | the MKII panel handshake |
| 6 | the UI's panel report check |
| 7 | the first audio frame interrupt entered |
| 8 | ... and returned |
| 9 | the clock check reached; velocity is the PLL multiplier byte (22 is 264 MHz) |
| 10 | the bootstrap-reprogram branch taken (must never appear) |
The module also sends notes for the DSP upload's record echoes and any stall, and for REMIX SWITCH's switch stages; the table in the module's source lists them.
Display Behaviour
Diagnostic MIDI output during boot. It adds no LCD page.
Status: on hardware: an MKII, 29 Sep 2026 (OCTABAM4-14); verify_boottrace.
Module facts (developers)
Probe: a MIDI note on MIDI OUT at each boot stage, the DSP upload's record echoes and any stall, for finding where a boot hangs.
| Detail | Value |
|---|---|
| Author | sanderlegit |
| Category | Reference |
| Kind | cf_patch |
| Test status | on hardware: an MKII, 29 Sep 2026 (OCTABAM4-14); verify_boottrace |
| Included in | no official remix |
On GitHub: https://github.com/sambanks/octabam/tree/main/modules/boot-trace