One community OS for the Elektron Model:Cycles, installed from your browser in about 30 seconds.
A Sampler machine · the Syntakt engines · MACRO and ACID machines · four LFOs per track · an arpeggiator · up to 546 BPM · and more
Open the web flasher · Read the guide · Every feature in detail · Join the Discord · Support on Ko-fi
Modded Cycles is a free, open-source firmware for the Model:Cycles (OS 1.13). It keeps Elektron's workflow and extends it: more machines, more modulation, better everyday gestures. It is not a rewrite of the OS, and it is not a mod store: what goes in is chosen for its value, its stability and how well it fits the rest.
Since version 2.0 there is a single OS, the Modded Cycles OS, instead of a list of mods to tick. Everyone runs the same firmware, so projects, tips and bug reports mean the same thing for everyone.
The flasher builds the firmware in your browser, from your own copies of the official Elektron files, and sends it to the machine over USB. Going back to the official firmware is one click away.
Important
No Elektron firmware is included in this repository, original or modified. You bring the official OS files from elektron.se; the OS is built from them on your computer. This is an independent project, not affiliated with or endorsed by Elektron. Flashing a modified OS is at your own risk and may void your warranty.
| Feature | What you get | Origin | Status |
|---|---|---|---|
| Sampler machine | Model-TG's Sampler as the 7th machine: samples from the internal storage with seven playback modes (one shot, loop, slice, granular, stretch, pluck, wave), slicing, resampling, a retrig page with 12 master effects, Attack, Filter and Resonance on the original machines, slide trigs, Scale Lock, sample upload through Elektron Transfer, a System page. | TinyGregAudio/Model-TG 1.1.0, MIT | 🧪 Experimental |
| Syntakt engines | Five real Syntakt machines, SD VINTAGE, CP VINTAGE, SY TOY, SY BITS and SY SWARM, as machines 8 to 12, with the Syntakt's knob names and defaults. Their code is read from your own Syntakt OS file. | Elektron's code, from your file | ✅ Tested |
| MACRO machine | Machine 13: the 47 synthesis models of Braids, Émilie Gillet's macro-oscillator. SHAPE picks the model, FUNC + PITCH gives lo-fi. |
pichenettes/eurorack, MIT | ✅ Tested |
| ACID machine | Machine 14: an acid bass in the style of the TB-303, with cutoff, resonance, env mod, drive, saw or square, and slides from your trigs. | RobinSchmidt/Open303, MIT | ✅ Tested |
| LFO 2, 3, 4 | Three more LFOs per track: on the LFO page, press LFO again. LFO 2 is saved with the sound and can be p-locked. |
After DavidCaruso | ✅ Tested |
| Arpeggiator | Hold several notes with RETRIG and they arpeggiate; FUNC + RETRIG sets direction and range, saved with the pattern. |
This project | ✅ Tested |
| Step record | Sequencer stopped, press REC twice: each note you play (TRIG keys, pads, MIDI) lands on the blinking step. PLAY skips, STOP goes back; knobs turned first become p-locks. |
This project | ✅ Tested |
| Easier trig removal | A quick press on a step that holds a trig removes it, instead of opening it as a hold. | This project | ✅ Tested |
| Trig preview | Sequencer stopped or paused: hold a step and press PAGE to hear it. |
drumkilla, via Model-TG | ✅ Tested |
| Tempo up to 546 BPM | The TEMPO knob, tap tempo, MIDI clock and saved projects go past 300 BPM. |
This project | ✅ Tested |
| Latching mute | Hold TRACK and tap FUNC: mute mode stays on. |
drumkilla, via Model-TG | ✅ Tested |
| Sample preview | On a Sampler track, in the preset menu, the track's pad plays the sample under the cursor. | This project, a piece of Model-TG | ✅ Tested |
| Scrolling names | Sound names too long for the screen scroll in the browser. | drumkilla, via Model-TG | ✅ Tested |
| Startup animation | The four squares of the modded-cycles logo pop in and “modded-cycles” types itself underneath. | This project | ✅ Tested |
| Multi-line browser | The preset browser shows three names at once in a small font. | This project, from a community idea | ✅ Tested |
| Volume and pan as numbers | On the main screen, LEVEL/DATA shows the track volume as a number; with FUNC, its pan. |
After djd_oz | ✅ Tested |
| Dimmed trigless trigs | A step that holds a trigless trig lights dimmed. | After djd_oz | ✅ Tested |
| Live MIDI OUT + THRU toggle | With THR selected, FUNC + press LEVEL/DATA adds the Cycles' own MIDI to what it forwards, or takes it away. |
AveyCole | ✅ Tested |
| Mod Settings: USB audio | SETTINGS has a last line, Mods, with the mods' own settings. USB Audio sends the computer the stereo mix (2CH, as stock) or each track on its own channel (6CH) to record stems; press LEVEL/DATA to switch, no reflash. |
6-channel audio after scottmetoyer/ms-multi-output, MIT | ✅ Tested |
The added machines come after Chord, always in this order: 07 Sampler, 08 SDVtg, 09 CPVtg, 10 SYToy, 11 SYBit, 12 SYSwm, 13 MACRO, 14 ACID.
Status of the OS itself: Experimental. Every feature was checked in an emulator that runs the OS's own code, and most were tested on a real Model:Cycles on their own, but this exact firmware (version 2.0) has not run on a machine yet. The status column above is the status of each feature.
Every feature, every key combination and every limit is written up in FEATURES.md. The guide on the website explains each one step by step, with the buttons to press.
- Per-track filter: stores its settings where LFO 2, 3, 4 store theirs, and does not work with Model-TG. It comes back once the Sampler side is rewritten.
- Optimised OS (the same sound with far less processor work): not compatible with the Sampler, MACRO, ACID and the Syntakt engines yet. Porting it to the OS is the next job.
- MIDI OUT while in THRU: the live toggle above does the same and more.
- Chord Keys was removed from the project on 18/10/2026 because of conflicts with the rest. Thanks to Nico Heuser for it; its code stays in the git history.
Developers can still build any of these from the command line (see BUILD.md).
- Open the web flasher in Chrome, Edge or Opera on a desktop computer (it needs Web MIDI). The first tab shows what the OS contains. There is nothing to pick.
- Drop your two official OS files:
model-cycles_OS1.13.syxfrom the Model:Cycles download andSyntakt_OS1.42.syxfrom the Syntakt download (1.41 works too; no Syntakt needed). Unzip them first. The Syntakt engines are read from the second file, on your computer. - Connect the Model:Cycles over USB and press Flash. Close Elektron Transfer first and leave the machine on its usual screen. The transfer takes about 30 seconds, then the Model:Cycles asks you to confirm with YES.
Everything runs in your browser: your files are never uploaded anywhere.
Before you flash, back up your projects and samples with Elektron Transfer, and set Device Config › Transfer to CYC.
Other ways to flash
- Classic method. If the fast method does not work on your setup, the flasher can also send the firmware the
way Elektron Transfer does through
CONFIG › UPGRADE(5 to 10 minutes). - Elektron Transfer. The flasher has a Download the .syx button: drop that file onto Elektron Transfer yourself.
- Command line. See BUILD.md.
Going back to the official firmware
First set any track that uses an added machine (7 to 14) back to one of the six original machines. Then open the flasher, choose the Official firmware tab, drop your official OS file and flash.
If something goes wrong
If a Model:Cycles ever stops starting, it can always be recovered from its startup menu (FUNC + power on, then
TRIG 4). That menu only listens to the MIDI IN port, so you need a USB-MIDI interface and the steps in
RECOVERY.md. The guide has a
troubleshooting section.
On a Model:Samples
The flasher installs the same OS on a Model:Samples (choose your machine in the first tab): its Sampler plays your
samples. It also needs the official model-samples_OS1.13.syx, and the way back to the Model:Samples OS is in the
Samples OS tab. The same tab can turn a Model:Cycles into a Model:Samples.
The web flasher is a port of a pure-Python toolchain that lives in this repository: no compiler and no firmware needed to build the OS.
python3 tools/build.py -i model-cycles_OS1.13.syx --syntakt Syntakt_OS1.42.syx --os -o modded-cycles-os.syxos.json at the root of the repository is the recipe of the OS. Details in BUILD.md; the developer
setup (toolchain, emulator, agents) is in DEVELOPMENT.md.
Every feature is a tweak: a table of byte changes applied to the user's own OS, plus code compiled or assembled into free space of the firmware. Each one is checked in an emulator that runs the Model:Cycles' own code, then on a real Model:Cycles before it is marked Tested. The Syntakt engines are not imitations: their code and tables are taken from your Syntakt OS file and relocated into the Model:Cycles firmware, and they produce the same samples as the Syntakt in emulation.
The research behind it (firmware analysis, hardware architecture, engine ports, measurements) is written up in the technical notes, in French. Release notes are on the website.
Bug reports, test reports and ideas are welcome on the Discord and in the issues. Code contributions follow CONTRIBUTING.md: a feature joins the OS when it is proven in emulation, tested on a machine, compatible with everything already in the OS, and wanted by the community. The tools and agents used to develop it are described in DEVELOPMENT.md.
This project stands on the work of others:
- TinyGregAudio/Model-TG (MIT): the Sampler machine and everything that comes with it (license).
- drumkilla/elektron-model-tweaks (MIT): latching mute, trig preview, scrolling names, and the
mtlibtoolkit and tweak format used by the build. - pichenettes/eurorack (MIT): Émilie Gillet's Braids code, compiled as is for the synthesis models of the MACRO machine (license).
- RobinSchmidt/Open303 (MIT): Robin Schmidt's TB-303 model, rewritten in fixed point for the ACID machine (license).
- DavidCaruso (LFO 2, 3, 4), djd_oz (volume and pan as numbers, dimmed trigless trigs), AveyCole (MIDI OUT + THRU), RDS (AIM) and DaftMaple (the OS on a Model:Samples), Nico Heuser (Chord Keys, 2026): community mods and ideas this OS grew from.
- scottmetoyer/ms-multi-output (MIT): the original 6-channel USB mod, behind the 6CH setting of Mod Settings.
- dagargo/elektroid (GPL-3.0): the Elektron Transfer update protocol behind fast USB flashing.
- mischa85/elektron-firmware-tool (MIT): the firmware container format and its signature, on which
mtlibis based. - mxldyn/octamax and bryantysinger/octa-bt-pt: reverse-engineering and patching methods (ideas only, no code).
Modded Cycles' own code, tweak files, website and notes are released under the MIT License. Third-party code keeps its own license: see THIRD-PARTY-NOTICES.md. No Elektron firmware is included or licensed here; Elektron, Model:Cycles, Model:Samples and Syntakt are trademarks of Elektron Music Machines MAV AB.
If this OS is useful to you, you can support the project on Ko-fi.