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▐░░  O T   K Y O T I   F W   ·   custom Octatrack firmware  ░░▌
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Welcome Elektron fans. I'm Zac Kyoti, a musician and music tech hacker located on the US west coast. This repo contains knowledge and tools that may be used to research and explore modifications to the Octatrack stock firmware.

Design Philosophy: KYOTI firmware is designed as a set of new or extended features, QOL improvements, and bugfixes, not available in the factory firmware, which can be applied individually, in combination, or as a comprehensive build. All mods are designed to cleanly interlock. The KYOTI firmware design perspective comes foremost from a place of deep respect and appreciation for the architecture of these instruments before any mod is applied. As such, my approach is to make the modded instrument "feel" like stock — customizations appearing seamless, respecting existing UX/UI conventions, and (ideally) stage-ready and bug-free. KYOTI firmware is not about complete overhaul of the instrument's plumbing (there are plenty of other projects that do that, which you may consider combining with KYOTI); it's more about making the stock instrument the best version of itself it can be. Read on and enjoy!

The features list on the main branch will be updated as new builds roll out.

Influenced by the concepts of mxldyn/octamax by Maxolydian and other Octatrack RE projects — full credits in CREDITS.md.

You bring your own copy of the official OS 1.40C; the tools here turn it into a modified image, byte-for-byte reproducibly from your copy. No Elektron binary is included or distributed. Every feature is off by default — a freshly flashed unit behaves like stock until you opt in. The bug fixes are always on.

How to build: BUILD_KYOTI.md. How to flash, and how to get back to stock: FLASHING.md.

Everything in this repo is work in progress until I promote it to final. Only final features are listed below. Every other build refuses to run unless you opt in:

KYOTI_ALLOW_WIP=1 python3 tools/build_<name>.py

An update to a final feature is work in progress too, until I promote it: the final build refuses to produce a changed image without the opt-in.

Hardware testing is on my Octatrack MKI; nothing here has been tested on an MKII, but the MKII panel layout has been considered for every build.

Choose how an audio track's mute behaves, in PERSONALIZE → MUTE MODE:

• OT — stock
• OTFX — a hard dry cut, but FX inserts ring out their tails and the sequencer keeps running underneath, so unmuting picks up where the pattern would have been
• OTFX-T — the same, and new trigs stay suppressed until you unmute
• DT-T — Digitakt-style: a sounding voice rides out its own amp envelope and FX, and only new trigs are suppressed

SOLO follows the same rule as a manual mute; CUE MUTES TRK stays a hard cut. The setting survives a power cycle.

Hardware: confirmed.
Final build: tools/build_mute_modes.py → OCTATRACK_OS1.40C_MUTE_MODES

An optional immediate pattern change, toggled with [PTN] + [YES] (a toast confirms; it is OFF at every power-on). A cued pattern takes over on the next step instead of waiting for the current one to finish, locked to the master clock: it plays exactly where it would be had it been running since START, whatever its track lengths, scales or master settings. The Part, START SILENT and trig conditions change as on a stock pattern change, and the last MIDI Program Change sent always names the pattern that plays. The arranger and chains are untouched; with DIRECT JUMP off, pattern changes are stock.

Hardware: confirmed: the clock-locked timing and the Part change. Not yet tested on hardware: MIDI tracks, Program Change on fast re-cues, START SILENT, and the trig-condition reset.
Final build: tools/build_direct_jump_kyoti.py → OCTATRACK_OS1.40C_DIRECT_JUMP_KYOTI

An external key input for the stock DynamiX COMPRESSOR, on the effect's page 2:

• KEY — which of the eight audio tracks drives the compression, even while it is muted
• KGN — trims the key signal
• KFLT — filters the key: below centre low-pass, above centre high-pass, centre off
• MON — auditions the filtered key

The DSP space comes from SPRING REVERB, which leaves the FX2 list; a project that still uses it loads it as NONE.

Hardware: confirmed.
Final build: tools/build_sidechain_compressor.py → OCTATRACK_OS1.40C_SIDECHAIN_COMPRESSOR

Reload one track's sequence from the CF card without stopping the transport:

• [PTN] + [TRACK n] — reload that track's card-saved sequence, Part untouched
• [BANK] + [TRACK n] — the same, and re-apply the saved Part

It reloads the pattern that is playing, on an audio or a MIDI track, and never restarts the sequence or the metronome. A toast confirms when the reload has finished, and says so if the trigs did not land.

Hardware: confirmed.
Final build: tools/build_reload_from_project.py → OCTATRACK_OS1.40C_RELOAD_FROM_PROJECT

Three new TSTR settings on a STATIC or FLEX track's SETUP page ([FUNC] + [SRC]). The sample follows the project tempo by varispeed, the way a classic sampler or a turntable would — speed and pitch move together, nothing is stretched. The tempo comes from the sample's own tempo attribute (audio editor, ATTR); a sample outside 30–300 BPM plays as stock.

• RPCH — the Octatrack's own playback, clean
• RPS9 — an Akai S900/S950: a virtual 40 kHz, 12-bit sampler
• RPSP — an E-mu SP-1200: 26.04 kHz, 12-bit, drop-sample, through its channel 1/2 low-pass filter, which the track's AMP envelope opens

On a repitch track the PTCH knob becomes QUAN, an exact ratio against the tempo — 1/2 2/3 3/4 4/5 1/1 5/4 4/3 3/2 2/1 — so a loop at 3/4 lines back up with the pattern. QUAN takes p-locks and scene locks, and PTCH and QUAN are kept separately. In the audio editor, TIMESTRETCH gains REPITCH, RPS9 and RPSP, so under SETUP AUTO each sample plays in its own mode. The DSP space comes from SPRING REVERB, as for SIDECHAIN_COMPRESSOR. Starts from Jannik Aßfalg's Repitch module for octabam (CREDITS.md).

Hardware: confirmed. Not specifically tested: RTRG retrigs on a repitch track, and a full DSP core of RPSP tracks under heavy effects.
Final build: tools/build_repitch_repeat98_kyoti.py → OCTATRACK_OS1.40C_REPITCH_REPEAT98_KYOTI

Reach the QUANTIZE LIVE REC setting from the front panel. Hold [REC] and tap [PLAY]: a toast shows the setting. Tap [PLAY] again while the toast is up to invert it. Once the toast has gone (1 s), a tap just shows the setting again. The first [REC] + [PLAY] still starts live recording as on stock.

Hardware: confirmed.
Final build: tools/build_quantize_live_rec_toggle.py → OCTATRACK_OS1.40C_QUANTIZE_LIVE_REC_TOGGLE

A trigless lock — a step with parameter locks but no audible trig — now disappears from the trig row once you erase its last lock, instead of staying lit. One placed deliberately with FUNC + TRIG is left alone.

Hardware: confirmed.
Final build: tools/build_erase_empty_trigless_locks.py → OCTATRACK_OS1.40C_ERASE_EMPTY_TRIGLESS_LOCKS

Mute a track's recorder trigs without deleting them. Hold [TRACK] and press [NO]: the held tracks' recorder trigs stop firing — a recording already running finishes — and a toast reads REC TRIGS MUTED. [TRACK] + [YES] brings them back (REC TRIGS UNMUTED). It works on any screen, with or without grid recording, and holds across pattern changes until you unmute; every track starts unmuted at power-on. A muted track shows two dots beside its play/stop icon at the screen edge (..■ / ..▶).

MIDI: CC 80 on a track's channel mutes it (1–127) or unmutes it (0); on the AUTO channel it acts on the active track. The keys send CC 80 (1 / 0) on each held track's channel. Both need AUDIO CC IN / OUT on, as for every audio-track CC. [FUNC] + [YES] / [NO] still arm and disarm one-shot trigs as on stock; [TRACK] + [YES] / [NO] now do this instead.

Hardware: confirmed. MIDI CC 80 not specifically tested.
Final build: tools/build_rec_trig_mute.py → OCTATRACK_OS1.40C_REC_TRIG_MUTE

Three fixes to stock bugs. Each has its own build.

• MIDI_PLAYS_FREE_FIX — a Plays-Free MIDI track with trig quantize Direct and pattern scale Per Track no longer stalls after its first step on a manual trig.
  Hardware: confirmed. Final build: tools/build_midi_plays_free_fix.py
• EMPTY_PATTERN_LED_FIX — a pattern whose only content is parameter locks now lights its grid LED under [PTN], instead of showing as an unused slot.
  Hardware: confirmed. Final build: tools/build_empty_pattern_led_fix.py → OCTATRACK_OS1.40C_EMPTY_PATTERN_LED_FIX
• PART_CHANGE_CARRYOVER_FIX — after a pattern-triggered Part change, a track leaving PICKUP for FLEX no longer keeps playing the old Part's pickup loop, and a switch into a PICKUP track no longer marks the Part edited when nothing changed.
  Hardware: confirmed. Final build: tools/build_part_change_carryover_fix.py → OCTATRACK_OS1.40C_PART_CHANGE_CARRYOVER_FIX

One image per feature above, with all three BATCH_BUGFIXES folded in — eight images, for flashing a single feature without giving up the bug fixes. The features are not combined with each other.

Hardware: every ingredient is confirmed on its own; these combined images have not been flashed as such.
Final build: tools/build_bugbuilds.py → out/Bugbuilds/OCTATRACK_OS1.40C_<FEATURE>_BATCH_BUGFIXES

Every feature above and all three BATCH_BUGFIXES in one image. The boot splash and SYSTEM STATUS → OS VERSION read KYOTI V1.0.

Hardware: confirmed.
Final build: tools/build_kyoti.py → out/KYOTI/OCTATRACK_OS1.40C_KYOTI_V1.0

This is for personal study. Updating an Elektron unit with anything other than official firmware is risky: it puts the warranty in question and can leave the unit needing the bootloader recovery path. Nothing here is endorsed by, supported by, or affiliated with Elektron. If in doubt, don't flash — just read, disassemble, and learn.

Keep the official .syx on hand: [FUNC] + power on → [TRIG 3] recovers the unit even from a bad OS, because an OS update never touches the bootloader. Never cut power during UPDATING FLASH. The full procedure and recovery net are in FLASHING.md.