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Firmware

openelixir-02

Loud91/100

Firmware for LXR desktop drum synthesizer

openelixir-02 is custom firmware for the Erica Synths LXR-02, by @tunefish777. Open source under GPL-3.0, latest release v1.2 (October 2026), 8 stars on GitHub.

forErica Synths LXR-02·by@tunefish777

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Download v1.2

LXR_OpenElixir-02_V1.2.img· 290 KB· +2 files

GPL-3.0· tunefish777/openelixir-02·downloads come from the creator’s GitHub releases

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OpenElixir-02

Build

Custom firmware for the Erica Synths LXR-02 drum machine. It is based on the open-source LXR V2 firmware by Erica Synths.

OpenElixir-02 is not official Erica Synths firmware and is not affiliated with or approved by Erica Synths. You install it at your own risk.

Goals

  • Sound and timing come first. Nothing has a higher priority than uninterrupted audio and a steady sequencer: menus, the display, the SD card and MIDI all wait for them.
  • More functionality, fully backwards compatible. OpenElixir-02 extends what is already there. Kits, patterns and projects from the stock firmware load and play as before, the MIDI implementation is unchanged, and the update works with the stock bootloader.
  • The stock sound stays available. Every change to the core sound of the unit comes with a switch in the config menu, so the stock sound is always one setting away.

Features

Kit management. Load full kits and single voices from any project:

  • Hold LOAD and press step button 1-7 (Drum 1 ... OP HH) to load just that voice from any kit of any project into the current kit.
  • "Change Project" below kit 0 in the load and save kit menus loads kits from other projects and saves kits into them.

Freely assignable voice engines. Each of the 6 voice slots can run any engine: drum, snare, cymbal or hi-hat. Select a voice and press SHIFT + KIT (or send NRPN 98). The engines are saved in the kit; kits from the stock firmware load with the stock engines.

Details for both: docs/ENGINES.md.

Limiter. Voices and FX are summed in 32 bit, followed by a limiter on each output, so loud kits no longer hard-clip. Levels that didn't clip before are unchanged. Config menu "lim" (2nd page) switches it off for exactly the stock mix.

DJ filter. A filter on the final mix of all outputs, on the performance page: dj turned left of the center is a low-pass (down to 40 Hz), right of it a high-pass (up to 8 kHz), around the center it is off; res sets the resonance. It isn't saved and starts off; while off, the sound is unchanged.

Uninterrupted playback. Turning knobs, working in the menus, loading and saving kits (also from and to other projects on the SD card) and saving projects don't interrupt the audio or the sequencer while it plays.

Under the hood. About 10 % less CPU load, many stock firmware bugs fixed (MIDI, sequencer, SD card, memory corruption; most found in the firmware review by jhw in erica-synths/lxr-desktop-app#3), and a project save that can't lose the saved project. Stock issues that are kept on purpose: docs/KNOWN_ISSUES.md. The changes of each version are in the release notes.

Building and installing

cmake --preset release      # add -DARM_TOOLCHAIN_DIR=<toolchain>/bin if arm-none-eabi-gcc isn't on PATH
cmake --build --preset release

This creates build/release/LXR_OpenElixir-02_V<version>.img. Copy it to the SD card and install it with the LXR-02's built-in updater (hold the encoder while switching on). The LXR prefix in the file name is required by the updater.

Every push is also built on GitHub Actions: the firmware files are attached to each run in the Actions tab, and the run summary shows the memory usage compared with the stock firmware.

Requirements, build options, the memory map, troubleshooting and development details are in the original firmware's README: README_LXR.md.

Licence

GPL-3.0-only, with the additional terms in NOTICE.md; see LICENSE. "Erica Synths", "LXR" and "LXR-02" are trademarks of Erica Synths, and the LXR hardware is their property.