You can build the firmware yourself using the Meshtastic firmware source:
- Clone the Meshtastic firmware repo.
- Follow the Meshtastic build instructions using PlatformIO.
- Use the
adafruit-nrfutiltool to convert the resulting.hexfile to.uf2.
You can convert .hex to .uf2 with this Python tool:
git clone https://github.com/microsoft/uf2
cd uf2/utils
python3 uf2conv.py path/to/your/firmware.hex -c -o firmware.uf2