adafruit-feather-nrf52840-sense: potential regression #21667
Description
Description
While updating https://github.com/smartuni/teamagochi to a modern RIOT version to showcase RIOT displaying stuff we noticed a weird issue when writing make term. Initially we assumed that this had to do with the project itself or our experiments on it. (Update branch: https://github.com/smartuni/teamagochi/tree/updated_for_jelly)
Over time the board would start having issues connecting as ttyACM0. Sometimes causing the programmer to even suggest that the board has a broken bootloader that needs to be reflashed. It also started having issues getting into the flash mode in the first place.
To properly verify that this wasn't related to the project itself, I then tried simply flashing examples/basic/hello_world onto the feather (Two different ones, both having the newest bootloader flashed onto it beforehand) and to my surprise the exact same issues was also happening on the most modern RIOT hello_world example (as of writing, https://github.com/RIOT-OS/RIOT/tree/543714fb757bff338a4b83cae0c4a1d77b0e44d3).
This, however, does not happen on the old version of teamagochi based on https://github.com/RIOT-OS/RIOT/tree/886c6a27099bed0157a3bc21fbcd221778bf834d. There are no issues whatsoever getting a terminal connection nor with the flashing process. (Branch: https://github.com/smartuni/teamagochi/tree/main)
To verify this I also flashed the hello world example from https://github.com/RIOT-OS/RIOT/tree/886c6a27099bed0157a3bc21fbcd221778bf834d and as expected it worked fine.
Steps to reproduce the issue
git checkout 886c6a27099bed0157a3bc21fbcd221778bf834d(Old version)cd examples/hello_word(Examples directory was different back then)make flash BOARD=feather-nrf52840-sense
Result: Terminal output works fine, you can reflash with no issues, ttyACM0 connects just fine
git checkout 543714fb757bff338a4b83cae0c4a1d77b0e44d3cd examples/basic/hello_world1.make flash BOARD=adafruit-feather-nrf52840-sense(Note that the board name changed inbetween)
Result: Terminal output rarely works, issues reflashing, once it breaks it can't find ttyACM0 at all anymore till you completely reflash the bootloader.
Versions
Operating System Environment
----------------------------
Operating System: "EndeavourOS"
Kernel: Linux 6.16.1-arch1-1 x86_64 unknown
System shell: GNU bash, version 5.3.3(1)-release (x86_64-pc-linux-gnu)
make's shell: GNU bash, version 5.3.3(1)-release (x86_64-pc-linux-gnu)
Installed compiler toolchains
-----------------------------
native gcc: gcc (GCC) 15.2.1 20250813
arm-none-eabi-gcc: arm-none-eabi-gcc (Arch Repository) 14.2.0
avr-gcc: missing
msp430-elf-gcc: missing
riscv-none-elf-gcc: missing
riscv64-unknown-elf-gcc: riscv64-unknown-elf-gcc () 15.1.0
riscv32-esp-elf-gcc: missing
xtensa-esp32-elf-gcc: missing
xtensa-esp32s2-elf-gcc: missing
xtensa-esp32s3-elf-gcc: missing
xtensa-esp8266-elf-gcc: missing
clang: clang version 20.1.8
Installed compiler libs
-----------------------
arm-none-eabi-newlib: "4.5.0"
msp430-elf-newlib: missing
riscv-none-elf-newlib: missing
riscv64-unknown-elf-newlib: "4.4.0"
riscv32-esp-elf-newlib: missing
xtensa-esp32-elf-newlib: missing
xtensa-esp32s2-elf-newlib: missing
xtensa-esp32s3-elf-newlib: missing
xtensa-esp8266-elf-newlib: missing
avr-libc: missing (missing)
Installed development tools
---------------------------
ccache: ccache version 4.11.3
cmake: cmake version 4.0.3-dirty
cppcheck: missing
doxygen: 1.14.0
git: git version 2.50.1
make: GNU Make 4.4.1
openocd: Open On-Chip Debugger 0.12.0+dev-gcf9c0b41c (2025-03-19-13:40)
python: Python 3.13.7
python2: missing
python3: Python 3.13.7
flake8: error: /usr/bin/python3: No module named flake8
coccinelle: missing