Hello everyone,

the RIOT OS uses the uf2conv.py script to program devices with the Adafruit nRF52 Bootloader.
Today we noticed some quirks:

1. Some distributions that don't necessarily use an automounter by default (like Arch Linux) don't necessarily use /media to mount devices but the more "tradutional" mount point /mnt. The uf2conv.py script currently does not search there.

2. When running uf2conv.py as root via sudo, it won't find any devices mounted by the user. This is because currently only the paths with /media/${USER} are checked. However ${USER}==root when using sudo. Therefore this PR adds a check if SUDO_USER is defined in the environment and adds /media/${SUDO_USER} to the search path.

chris@W11nMate:~$ sudo python3
[sudo] password for chris:
Python 3.10.12 (main, Feb  4 2025, 14:57:36) [GCC 11.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> os.environ
environ({'LANG': 'C.UTF-8', 'LS_COLORS': '...', 'TERM': 'xterm-256color', 'DISPLAY': ':0',
'PATH': '/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin', 'MAIL': '/var/mail/root', '
LOGNAME': 'root', 'USER': 'root', 'HOME': '/root', 'SHELL': '/bin/bash', 'SUDO_COMMAND': '/usr/bin/python3', 
'SUDO_USER': 'chris', 'SUDO_UID': '1000', 'SUDO_GID': '1000'})
>>>

3. One of our students noticed that the os.path.isdir(rootpath) check is redundant. I guess that that like should've been os.path.isdir(os.path.join(rootpath, d)) to see if the path is valid before adding it to the drives variable.

Best Regards,
Chris