Working with the Open Source MNT Reform Keyboard 4.0 on OpenSuSE

If you find any issues with the instructions then do not hesitate to create an issue here
This document is under European Union Public License 1.2 (EUPL-1.2).

Changelog

Date Description
2025-06-28 Initial tutorial showing how to upgrade the firmware under OpenSuSE Tumbleweed with cross-compiling

Introduction

The MNT Reform Keyboard 4.0 is an open source hardware and software mechanical keyboard with LEDs manufactured by the German company MNT Research. The keyboard uses only standard and open source components, so it is easy repairable. You can use it as an external keyboard to any computer or as an embedded keyboard into MNT Research's own laptops (e.g. MNT Reform, MNT Reform Pocket).
You can find the


The MNT Research team does not indicate any specific IDE to be used. If you do not have any preferred IDE then the Eclipse Theia IDE is a good starting point in all environments.
I will focus in this document on using it under OpenSuSE with an off-the-shelf x86-64 laptop.

Updating the Firmware with cross-compile

You may want to update the firmware of the keyboard either to have the latest features provided by MNT Research or because you have implemented yourself new features (e.g. related to LEDs, a different layout etc.). There is some documentation to do this (e.g. for the keyboard 4.0), but it does not take into account OpenSuSE or x86-64 architectures.
One challenge is that the firmware itself runs on a RP2040 and we want to here use an off-the-shelf laptop based on x86-64. There is a simple solution to this: cross-compile. This sounds only complicated and is very easy if you follow the instructions here.

First, we need to install some packages, such as compiler, that are needed to build the firmware:

Now we can clone the MNT Reform repository.

Afterwards we need to clone the Raspberry pico sdk as it is an important dependency for the firmware.
The initialization of the submodules is important - otherwise you will see later compile issues. You will need it as well if you update (git pull...) the pico-sdk repository.

Then, we can build the firmware.
Keep in mind that


Execute the following commands

Now we can flash the firmware on the keyboard.
Connect the keyboard to your computer and press the Circle key + x. The keyboard allows now to flash the firmware.
Execute the following commands

Afterwards do not forget to check if the version is indeed the one you specified by pressing the Circle key + s. It should be shown on the keyboard screen.