I tried to flash an Adafruit Feather Express and and an Adafruit Feather Sense following the documentation on Adafruit Feather nRF52840 Express. After manual mounting the device, the “flashing” (i.e., resetting the device into bootloader and copying the elf file onto the device) seems to succeed. However, after resetting the device, it seems to boot the original firmware again. I tried with
According to the
INFO_UF2.TXT on the device this is the running version of the bootloader:
UF2 Bootloader 0.2.6 lib/nrfx (v1.1.0-1-g096e770) lib/tinyusb (legacy-525-ga1c59649) s140 6.1.1^M Model: Adafruit Feather nRF52840 Express^M Board-ID: NRF52-Bluefruit-v0^M Bootloader: s140 6.1.1^M Date: Dec 21 2018^M
I don’t own a SEGGER J-Link but an nrf52dk - can this be used for debugging and flashing as well?