The only difference between the RAK4631-R (RUI3) and the RAK4631 (Arduino) is the bootloader it is shipped with - the hardware is the same.
Meshtastic requires the Arduino bootloader on RAK WisBlock NRF52-based boards. The process of converting the bootloader only needs to be performed once.
- Install Python
- Install pyOCD
pip3 install pyocd
- Download the required bootloader: WisCore_RAK4631_Board_Bootloader.hex
- Connect the RAKDAP as follows:
- Flash the bootloader
pyocd flash -t nrf52840 .\WisCore_RAK4631_Board_Bootloader.hex
- Continue with the normal flashing instructions
Alternate methods of flashing are outlined here.