Thanks, @beeegee and @k3nt.
As indicated at the beginning of this thread, I am trying to get this to work on either Linux or Windows (ideally both but I’ll at least be able to proceed for now with whichever works). I will try the Windows fix later. For now, though, I am on Linux and, after successfully installing ble_ota_dfu.ino (progress!), I get the following when attempting to burn the updated bootloader:
Usage: adafruit-nrfutil dfu serial [OPTIONS]
Try "adafruit-nrfutil dfu serial --help" for help.
Error: Invalid value for "-pkg" / "--package": File "/home/jg/.arduino15/packages/rakwireless/hardware/nrf52/0.21.20/bootloader/WisCore_RAK4631_Board/WisCore_RAK4631_Board_bootloader-0.3.2_s140_6.1.1.zip" does not exist.
Error while burning bootloader.
This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.
This error seems to indicate that the path to the package with the correct bootloader is wrong.
Attempting to further troubleshoot, from WisBlock/bootloader/RAK4630/new/Adafruit_nRF52_Bootloader_new at master · RAKWireless/WisBlock · GitHub, running
git submodule update --init appeared to run successully. Still no luck burning the bootloader.
Presumably there is a path setting somewhere that needs to be changed although I am not sure if that is something I can do or if it is in the “burn” code.
Note that I have not updated the BSP per GitHub - RAKWireless/RAKwireless-Arduino-BSP-Index: RAKwireless BSP Support for the Arduino Board Manager. I am hesitant to do so unless/until I get this bootloader issue resolved.