An unofficial community remixer for the Elektron Octatrack's operating system, not affiliated with Elektron: pick the modifications you want and build them into one firmware image from your own copy of OS 1.40C.

A modification is a module (modules/<name>/). A named selection of modules is a remix (remixes/<name>/). make image REMIX=<name> composes a remix into a card-flashable image: it places the code, wires the hooks by symbol, refuses collisions by name, and proves every ported module against its author's own build byte for byte. No firmware is distributed here; every image is derived from the user's own 1.40C on the user's machine, and a built image must never be shared.

Every module is contributed by its author and credited in the table below. Pull requests are accepted: a module, a port of an existing mod, a fix, a doc correction. Issues are disabled and there is no request queue. The licence is MIT; a fork that takes requests and tracks issues is allowed.

docs/guide/BUILDING.md has every step. Section 0 is what to install first: on macOS the Xcode Command Line Tools (xcode-select --install), Homebrew, Python 3.10+ and brew install cmake uv. Then make setup, make emu-setup, make os && make recon, make image REMIX=<name> BUILD=1, and the flash from the card (section 5).

modules/<name>/manifest.py   what a module is and what it claims (yours, or a pointer into an author's repo)
remixes/<name>/remix.py      which modules, in which chooser order; README.md beside it
remixes/test/<name>/         a remix of one module, for that module's gates
tools/remix/ledger.py        refuses two modules that claim one address, hook, id or buffer, by name
tools/build/build_bus.py     the build: assembles, links, places, wires, verifies -> out/mainos_bus.bin
tools/verify/*               the gates: oracles, the boot under the ColdFire port, menu, cycles, identity

A module's code lands in one of three places; the build decides which bytes go where, and a module declares what it is, not an address:

The OS-image edits every class needs (a detour at a stock instruction, a poke, a grown table) are Detour, Poke, TableGrow, wired by symbol and asserted against stock before a byte is written. docs/contributing/PLACEMENT.md is the map of what is free and what was measured.

A port is a proof. The build re-links every unit at the author's own address and compares, rebuilds Octakit's runtime to the identities her recipe pins, and refuses on any drift.

Where a module's state lives. An effect's twelve knobs are Part parameters and stay in the Part. Personal material (Octakit's Kits, octalab's grooves) is in files the module owns and formats. A module's settings (menu options, a USB profile) have no shared home yet; the shared settings store for all modules, OTX, is specified in docs/proposals/OTX_PROJECT_PROPOSAL.md (nordseele, draft 2, 26 Sep 2026) with author-facing guidelines, and is not implemented.

Everything is checked on your machine against your own 1.40C (docs/contributing/TESTING.md). The DSP side renders locally on the assembled instruction stream (make render, make render-rig; tools/harness/README.md). The whole machine, the ColdFire, both DSP cores, the card, the panel, MIDI and USB, runs under a port of it (tools/emu/ot_emu, make emu-cf; tools/emu/README.md):

make check REMIX=<name>             # build + every gate + boot under the port; OT_PROJECT=<dir> adds a real project
make reach                          # the gates this branch's diff reaches, in order; RUN=1 runs them
make panel REMIX=<name>             # the virtual front panel with sound at localhost:8563 (tools/panel/README.md)
make emu-live REMIX=<name>          # the screen and keys in a window, no sound

CI (.github/workflows/ci.yml, make ci) runs the checks that need no firmware. What the emulators cannot see (caches, the recorder's DMA, cross-core timing) is listed beside every gate that is blind to it.

Writing a non-official OS to an Octatrack can leave it unusable and puts your warranty in question. Nothing here is endorsed by, supported by, or affiliated with Elektron. BUILDING.md has the recovery path (section 7).

No Elektron binary is redistributed here, and none may be. A built .bin or .syx contains Elektron's OS: do not share built images. Share the repo; everyone builds their own.

Octatrack and Elektron are trademarks of Elektron Music Machines MAV AB, used here only to identify the hardware this project targets.

docs/README.md lists every doc by who it is for. Each module's page is modules/<name>/README.md, each remix's remixes/<name>/README.md, and each tool's tools/<dir>/README.md.

CONTRIBUTING.md    your first PR, the module contract, the oracle rule, the gates, what CI checks
AGENTS.md          instructions and traps for coding agents (CLAUDE.md imports it)
.github/           CI (Ubuntu + macOS, SHA-pinned actions), the PR template
modules/           the contributions, one directory each, each with its README
remixes/           one directory per remix: remix.py (the selection, in chooser order) and README.md; README.md here is the index
remixes/test/      the one-module remixes, for their modules' gates (make check REMIX=<name>)
docs/guide/        building, flashing and composing a remix
docs/contributing/ writing a module, testing, placement, tooling, the failure register
docs/firmware/     the firmware, reverse-engineered
docs/proposals/    technical propositions
tools/remix/       the toolkit: schema, registry, ledger, the loader, the DRAM platform, the TUI
tools/build/       the image build (build_bus.py) and the tools that understand the OS layout
tools/verify/      the gates
tools/harness/     hear and measure the DSP side locally (dsp_host, send_probe, rig_render)
tools/emu/         the ColdFire emulators: the headless port (ot_emu) and the Unicorn bring-up
tools/panel/       the virtual front panel over the port, with sound
tools/hw/          the unit and its card: MIDI control, capture, project files, MIDI flashing
tools/ghidra/      one Ghidra project over the OS and both DSP payloads
tools/patches/     local patches to the vendored toolchains
scripts/           toolchain setup, vendored pins (vendor.sh), OS fetch and recon, the bit-identity gate
dsp/               shared DSP infrastructure: the null stub and the probes

Em (emuyia) designed Octakit and the loader-appended DRAM runtime octabam adopted as its large-payload placement; tools/remix/loader.S is derived from hers with attribution. Her repository invites use as a submodule to combine with other efforts.

This began as a fork of mxldyn/octamax by Maxolydian, whose reverse engineering of the OS format, memory map and parameter tables made any of this reachable; the upstream history is in this repository's log.

vendor/ pulls in dsp56300, mc68k and elektron-firmware-tool.

MIT for this repository's own code and documentation. It does not extend to Elektron's firmware, which is not distributed here, nor to the repositories referenced as submodules, which remain their authors' under their own terms. THIRD_PARTY.md lists every transcribed DSP source (Airwindows, JClones, Mutable Instruments, ChowDSP, jpcima, audiojs), the submodules and the vendored tools, each with its licence.