Erica Synths LXR-02 firmware goes open source under GPL-3.0

Erica Synths has published the source code of the LXR-02 firmware on GitHub, for the digital drum machine it co-designed with Julian Schmidt (Sonic Potions). The erica-synths/lxr-desktop-app repository received its first commit on 20 October 2026 and its licence on 23 October. The news was first reported by Synth Anatomy; Erica Synths has not issued a press release. The LXR-02 shipped with a closed operating system, whereas Sonic Potions’ original LXR (2014) was already open, so the new machine now follows its predecessor.

What the repository contains

Despite its name, the repository holds the full firmware rather than a desktop app: the code running on the machine’s STM32F765 microcontroller (a 216 MHz Cortex-M7 core):

• the drum voices and the FX bus;
• the step sequencer;
• MIDI over DIN and USB;
• preset storage on SD card;
• the user interface (LCD and buttons), plus the update format used by the bootloader (the small program that installs updates).

Licence: GPL-3.0, with clear limits

The firmware, bootloader and build system are released under the GPL-3.0: anyone can modify the code and distribute their own version, as long as they publish the source. The README sets three boundaries:

• modified firmware must be clearly marked as modified and never presented as official;
• the “Erica Synths”, “LXR” and “LXR-02” trademarks are not covered by the GPL;
• the hardware stays closed: schematics, PCB layouts and industrial design are not in the repository.

An LXR-02 voice at a glance

Each of the six voices (three “Drum” voices, snare, clap/cymbal, open and closed hi-hats) runs on a digital FM synthesis engine, where one oscillator modulates another to produce metallic or percussive tones; the principle is covered in our FM and additive synthesis section. More than thirty parameters are available per voice, grouped into sections:

The amp envelope follows the logic explained in our ADSR envelope explainer, in a shorter form suited to percussion. The sequencer runs to 64 steps, with mutes, rolls and kit morphing. The front panel shows a stereo main output, a second stereo output, headphones, MIDI DIN in and out, USB, an SD card slot, clock in and out and a reset input.

Erica Synths has an official demo:

Building and installing: at your own risk

Building requires CMake 3.21 or later, Ninja, the Arm GNU toolchain and Python 3. The result is an LXR_V2_V<version>.img file that installs like an official update: copy it to the root of a FAT32 SD card, then power the unit on while holding the encoder.

Erica Synths does not support self-built or modified firmware: installing it is at your own risk.

The SD card remains the recommended route. The flash_full target, meant for development and repairs with an ST-Link debug probe, overwrites the bootloader: if interrupted, the unit may no longer update from SD. According to Synth Anatomy, repairing a bootloader damaged by third-party firmware is charged. Official firmware is still available from the product page; the latest version listed is 1.71, dated 23 May 2025.

Who it is for, what it costs, what it competes with

Who it is for. First, LXR-02 owners comfortable with embedded C, who can fix a behaviour, add a sequencer feature or a voice algorithm. Then every other owner, who will benefit from community firmware without writing a line. Finally, prospective buyers: open firmware extends a machine’s life beyond the maker’s support.

What it costs. The code is free. The LXR-02 is listed at €490 excluding VAT on Erica Synths’ shop, shown as out of stock on 26 October 2026. View at Thomann

What it competes with. Korg’s drumlogue opens a single part to third-party engines through the logue SDK, but its system stays closed. Elektron’s Model:Cycles, also a six-track FM-based machine, is fully closed. The LXR-02 becomes the most open of the three, provided you accept the risk of unofficial firmware. It is part of a wider trend: this month Mutable Instruments opened the Beads code and M-VAVE released an SDK for its FM1. Erica Synths has also announced another drum machine, the Konstrukt-8.

More rhythm machines in our Drum Machines section.