An unofficial, browser-based workbench for owners of the Elektron Syntakt. You load the official OS 1.41 file that you downloaded from Elektron, make your changes in a tool, and the page builds a new file for you to flash yourself. Everything happens in your browser tab. Nothing is uploaded, and the site cannot talk to your instrument.

Not affiliated with, endorsed by or supported by Elektron. Syntakt and Elektron are trademarks of their owner.

• Make sure you can put the official firmware back before you flash anything. Try the restore procedure from the Syntakt manual once, with the official file, before you need it.
• Flashing modified firmware can leave your instrument unusable, and it voids your warranty. You do this entirely at your own risk.
• Back up your projects and sounds with Elektron Transfer first.

SY CHORD Wave Bank - put your own single-cycle waves into the SY CHORD machine. You pick them with its WAVE knob, as before.

• 31 waves can be changed (WAVE 4, 8, 12 ... 124); the values in between morph from one wave to the next.
• Takes single-cycle WAV files of any length, 8 to 32 bit, mono or stereo (left channel is used).
• Makes chord waves: one wave that holds a whole chord (major, minor, sus, diminished, augmented, sixths, sevenths, ninths), in any inversion. With the default tuning the root is four octaves above the note you play, so lower TUNE to bring the chord down; "Pure intervals" tunes every interval exactly instead.
• Fills many waves at once from a WaftWave bank (.json) or a ZIP of WAV files. A bank with more waves than fit can be spread evenly over the free waves.
• The tool resizes each wave to one cycle, centres it, sets it to full level, lines it up to start at zero and limits its brightness (40 harmonics by default, adjustable for each wave).
• Replace one wave, or insert a wave so that the waves above it move up one step.
• The small wave picture on the Syntakt screen is redrawn to match your waves (checked on an instrument on 22 September 2026). You can switch it off in the tool's Settings; then only the sound changes.

Files built with this tool were flashed onto a Syntakt running OS 1.41 and measured from the instrument's own audio output (September 2026):

• a saw and a square wave came out within 1% of the waves that went in, over 40 harmonics;
• every WAVE value that was left alone measured exactly as it did before;
• adding a second change to a file that had already been changed was tested the same way;
• the screen pictures were checked by eye on the same unit: a square, a triangle, a saw and a pulse showed up as those shapes, and untouched WAVE values kept their original pictures;
• a chord wave and a wave from a WaftWave bank were played and looked at on the same unit on 23 September 2026.

Before it offers a download, the page checks that the new file differs from the official one only in the parts that hold the SY CHORD waves and their pictures.

• OS 1.41 only. Any other file is refused rather than changed blindly.
• WAVE 0 is a sine that other machines also use. It is locked by default; if you unlock and change it, those machines change too.
• SY CHORD keeps one copy of each wave for all notes, so very bright waves sound harsh on high notes.
• Patterns and sounds that use a WAVE value you changed, or one next to it, will sound different. Flash the official file to get everything back.

Deja Vu LFO - two new LFO shapes, DV-F and DV-T, after RND on the WAVE knob of every LFO. Each is a loop of random steps; the behaviour is inspired by the Deja Vu control of Mutable Instruments Marbles.

• SPH sets how the loop behaves: at 0 it plays new values all the time, at 64 it repeats, at 127 it plays the same values in a new order.
• MODE sets the length of the loop: 2, 4, 8, 16 or 32 steps. The MODE cell shows the number.
• DV-F keeps running on its own; DV-T starts the loop again on every note.
• The seven original shapes are unchanged.

Checked on a Syntakt running OS 1.41 on 23 September 2026, on its screen and by ear: every loop length, SPH 0, 64 and 127, DV-T restarting on notes, both LFOs of a track and several tracks. The file the page builds is byte for byte the one that was checked. OS 1.41 only; a sound saved with DV-F or DV-T plays a different shape on the official firmware.

• A safer test loop - every change that touches program code is now tried in an emulator before it goes anywhere near a real instrument (the digikit emulator, a separate GPL project, unmodified in spirit: it runs our firmware file, we do not ship it). Data-only changes (waves, pictures) never needed this.

If you are working on something similar, or want to, open an issue first so we can avoid doing the same thing twice.

No Elektron firmware, no factory sounds and no excerpts of either. You supply your own official file; everything the page shows is read from that file on your own computer. Do not add firmware files, images built with the tool, or anything extracted from them to this repository, to issues or to pull requests.

tools/syntakt_os_flash.py (Windows, Python 3.8 or later, no packages) sends an OS file to a Syntakt over USB the way Elektron Transfer does, and confirms the upgrade itself, so the instrument does not ask "UPGRADE OS NOW?". The Syntakt still checks the whole file before it writes anything.

python tools/syntakt_os_flash.py check              talk to the Syntakt, change nothing
python tools/syntakt_os_flash.py probe FILE.syx     send the start of FILE, then cancel
python tools/syntakt_os_flash.py flash FILE.syx     flash FILE (you type FLASH to confirm)

• Make sure you can put the official OS back first (Early Startup Menu, OS UPGRADE, over a MIDI DIN cable). The instrument does not ask again, so check the file name twice.
• Close Elektron Transfer first: only one program can use the Syntakt's MIDI port.
• The script prints the file's SHA-256 and says whether it is the official OS 1.41 file.
• Tested on one Syntakt on OS 1.41 in September 2026: this script flashed an image built here, and the same sequence flashed the official file. It uses the connection Transfer uses, which Elektron does not document; another OS may change it.

python web/dev/serve.py 8765

Then open http://127.0.0.1:8765/ . The small server only exists to stop the browser from caching JavaScript modules while you edit them.

node web/test/dsp.test.mjs

runs the tests that need no firmware file.

• elektron-firmware-tool by mischa85 (MIT) - the file-format groundwork that Elektron firmware projects build on.
• dn2_firmware_explore - the model for a browser-only tool that works on the owner's own file.
• digikit - its notes on the Elektron MIDI connection were the starting point for syntakt_os_flash.py (the script is our own code; no digikit code is included).
• Mutable Instruments Marbles by Émilie Gillet - the Deja Vu idea behind the Deja Vu LFO tool.

MIT - see LICENSE. The license covers the code and text in this repository only.