octabam2elemod
sambanks/octabam's Octatrack modules as
elekloader mods (.elemod), for the
Octatrack MKI and MKII on OS 1.40C.
- What they are. 34 mods, converted from octabam commit
363861e(30 Sep 2026) by elekloader's converter. - Where they are. The files are in this repository's releases. They are also in the mod shop on elekloader's web page.
- Who wrote them. The code is octabam's and its contributors': Sam Banks, Tim Hastie, Mark Roberts (octemu), Bryan T, repeat98 and bkkbrls-del. This repository only converts it, and makes no claim on it. Problems with a mod's behaviour that also happen in octabam's own build belong upstream.
On a unit so far (an Octatrack MKII, 3 Oct 2026; details under On a unit):
- Tested in use, all working: 15 mods.
- Boot, not yet tested in use: 4 more.
- Not yet run on a unit: the other 15 USB layouts.
Nothing has run on an MKI. Keep your stock OS file, and read Recovery before you flash.
Use them
- Get your stock OS from Elektron:
OCTATRACK_OS1.40C.syx(or the.zipit comes in). - Open elekloader, either the web page
or the desktop app (0.4.0 or later). Add the stock file, then add mods from
the shop or from the
.elemodfiles here. Then build. - Flash the
.syxit gives you as any OS update, or put the.binon the card.
Every mod here needs the Octatrack core (core-ot-0.1.elemod). elekloader
includes it and ticks it for you.
Which USB mod
Take at most one of these. Each carries what it needs, so elekloader refuses two together.
| you want | take |
|---|---|
| USB MIDI only | octabam-usb-midi |
| the Octatrack as a USB audio input to the computer (it records the OT), with USB MIDI | one octabam-usb-audio-out-*, and add octabam-usb-crossbar beside it |
| a USB audio interface both ways (the computer also plays into the OT's inputs), with USB MIDI | one octabam-usb-io-*: it includes USB CROSSBAR |
The usb-io mods take SPATIALIZER off both FX menus. Its DSP code space
holds the code that brings the computer's audio in, as in octabam's own
usb-io builds. A part that had SPATIALIZER shows NONE there, and that slot
passes its audio through unprocessed.
USB audio is class compliant (UAC2, 44.1 kHz, 24-bit). octabam has measured it on macOS. It has not been measured with Windows or Linux hosts.
Other combinations
Everything else combines freely, with one exception: MIDI SCENES and SCENES P2 keep data in the same bytes of every Part, so they are refused together (octabam refuses the same pair).
The mods
| file | what it does | from |
|---|---|---|
octabam-cc-feedback | every knob change goes out as its MIDI CC, so a controller's encoders follow the unit | sambanks |
octabam-cc-map | MIDI CC 62-67 drive FX2's page-2 knobs, 68-73 FX1's | sambanks |
octabam-direct-jump | CHAIN AFTER: DIRECT. A pattern change lands at the next step, the step count continuing (Analog Four / Rytm direct jump) | Tim Hastie |
octabam-flex-seekbind | a FLEX re-bind of the same sample seeks in place instead of starting a new note | sambanks |
octabam-flex-seekbind-ctr | pairs with FLEX SEEK BIND: such a re-bind keeps the voice's bind counter | sambanks |
octabam-lofi-amf-fix | fixes the stock LO-FI effect's AMF knob | Bryan T |
octabam-midi-scenes | scene locks from MIDI: hold, morph, save, reload, clear, copy, paste | bkkbrls-del (midisc) |
octabam-quantizer | PROJECT > CONTROL > SEQUENCER > SCALE: PTCH and the CHROMATIC keys follow one of 24 scales, with a root and a synth glide | Tim Hastie |
octabam-recorder-hold | a FLEX voice reading past the end of a recording holds the last sample instead of dropping to zero | sambanks |
octabam-recorder-spacing | a fixed-RLEN recording lasts exactly until the next arm | sambanks |
octabam-repitch | TSTR REPITCH: follow the project tempo by playback speed, without grains | repeat98 |
octabam-rlen-plen | RLEN PLEN: one loop of the track's pattern, so TRIG ONE + QREC PLEN records the next pass and stops | sambanks |
octabam-scenes-p2 | scene locks and the crossfader reach FX1/FX2 page 2 | sambanks |
octabam-synth | a FLEX track whose sample is named SYNTH* plays a two-operator FM voice | Tim Hastie |
octabam-tuner | UP + TEMPO opens a tuner for the current audio track | Tim Hastie |
octabam-usb-midi | class-compliant USB MIDI in and out, mirroring the DIN ports | Mark Roberts (octemu) |
octabam-usb-crossbar | gives the USB controller first claim on memory, which cures lost USB audio packet tails | Bryan T |
octabam-usb-audio-out-tracks-main-cue | 20 channels to the computer: the eight tracks in stereo (post-FX, pre-fader), MAIN and CUE | Mark Roberts, Bryan T |
octabam-usb-audio-out-tracks | 16 channels: the eight tracks in stereo | Mark Roberts |
octabam-usb-audio-out-main-cue | 4 channels: MAIN and CUE | Mark Roberts, Bryan T |
octabam-usb-audio-out-main | 2 channels: MAIN | Mark Roberts |
octabam-usb-audio-out-master | 2 channels: track 8, the master track | Mark Roberts, Sam Banks |
octabam-usb-io-<out>-<in> (12) | a USB audio out layout above (tracks-main-cue, tracks, main-cue or main), plus the computer's audio into inputs A/B (ab), C/D (cd) or A to D (abcd, 4 channels). While the computer's stream is closed, the inputs are the jacks again. | Mark Roberts, Bryan T |
Each file is named octabam-<module>-363861e.elemod. The audio-out mods each
include USB MIDI.
How they were made, and what was checked
elekloader's converter (python -m elekloader.sdk.octabam) reads octabam's
module manifests. It turns each module into a linkable mod for the
Octatrack's core, and checks the result against octabam's own account of the
bytes: every cave and unit equals its source linked by GNU ld at the same
address, and every patch site holds what octabam's build would write there.
- USB AUDIO OUT. octabam writes the USB device descriptor's class in place, inside the bootloader copy that elekloader never lets a mod change. These mods serve a copy of the 18-byte descriptor from their own memory instead, so the computer reads the same bytes and the bootloader copy stays stock.
- USB IO. These are octabam's
usb-io-*remixes, each converted as one mod. The bytes octabam's build writes beyond its modules (the DSP code in SPATIALIZER's space, its hook, the FX menus) are taken from octabam's own build of that remix. Linked with the core, each one's OS image equals that build in every byte except six: the pointer to the descriptor copy, and the three bytes it serves. - The USB gates. octabam's own USB gates pass on elekloader builds of all
17 USB audio mods, in octabam's ColdFire emulator:
verify_usb: enumeration, every channel carries its own source, counters, full speed, MIDI both ways;verify_usb_in(the 12usb-io): the computer's samples reach the inputs bit-exact, and the jacks return when the stream closes.
What this cannot show is anything a real unit adds: timing, a real host, long sessions.
On a unit
3 Oct 2026, an Octatrack MKII. Eight builds were flashed from the card, and each booted showing its own version:
| build | what it carried |
|---|---|
| T0 | the core alone |
| T1 | FLEX SEEK BIND, FLEX SEEK BIND CTR, RECORDER HOLD, RECORDER SPACING, LOFI AMF FIX, RLEN PLEN, DIRECT JUMP |
| T2 | USB MIDI, CC MAP, CC FEEDBACK, MIDI SCENES |
| T3 | TUNER, SYNTH MACHINE, SCALE QUANTIZER, REPITCH |
| T4 | SCENES P2 |
| T5 | USB AUDIO OUT TRACKS MAIN CUE, USB CROSSBAR |
| T6 | USB IO TRACKS MAIN CUE AB |
| T7 | the 14 non-USB mods but SCENES P2, and USB IO TRACKS MAIN CUE AB |
They were built from this release's files and elekloader 0.4.0's core.
Then T7 was tested in use (the checks in the test plan), and everything worked. So, mod by mod:
| status | mods |
|---|---|
| tested in use, all working | TUNER, SYNTH MACHINE, SCALE QUANTIZER, REPITCH, DIRECT JUMP, RLEN PLEN, MIDI SCENES, CC MAP, CC FEEDBACK, RECORDER HOLD, RECORDER SPACING, FLEX SEEK BIND, FLEX SEEK BIND CTR, LOFI AMF FIX, USB IO TRACKS MAIN CUE AB |
| boots, not yet tested in use | SCENES P2, USB MIDI, USB CROSSBAR, USB AUDIO OUT TRACKS MAIN CUE. The last three are also part of USB IO TRACKS MAIN CUE AB, which was tested; these files on their own were only booted. |
| not yet run on a unit | USB AUDIO OUT TRACKS, MAIN CUE, MAIN and MASTER, and the eleven other USB IO combinations |
Nothing here has run on an MKI.
This section grows as checks pass. The shop's details sheet says the same for each mod.
To make them yourself, see convert.sh.
Recovery
If a build misbehaves, go back to stock:
- Hold FUNC while powering on, for the startup menu.
- Press TRIG 3 (MIDI UPGRADE).
- Send the stock
OCTATRACK_OS1.40C.syxover 5-pin MIDI (not USB).
elekloader never changes the bootloader.
Licence
MIT, from the code it is built from: octabam (Sam Banks), octatrick-modules (Tim Hastie) and octemu (Mark Roberts). Every notice is in LICENSE. No file here contains Elektron firmware. Octatrack and Elektron are trademarks of Elektron Music Machines MAV AB. Nothing here is made or endorsed by Elektron.