Backstory:
So this issue is the result of a bug recently introduced in Debian Bullseye (which includes current PiOS). The bug prevents the symlinks in /dev/serial/by-id/ from being created.
You can read about the bug here:
Debian Bug Report Logs
Identify the Problem:
If you can’t connect to the cutter anymore after a system update, you can check if it is caused by that bug by checking the installed version of udev with:
apt show udev
If your version is 247.3-7+deb11u2 or 247.3-7+rpi1+deb11u2 you have the broken package installed and should use the fix below.
The Fix:
- Backup the existing rules file (just in case you need it when this bug gets sorted out)
sudo cp /usr/lib/udev/rules.d/60-serial.rules /usr/lib/udev/rules.d/60-serial.old
- Download the correct rules file from the systemd main repository
sudo wget -O /usr/lib/udev/rules.d/60-serial.rules https://raw.githubusercontent.com/systemd/systemd/main/rules.d/60-serial.rules
- Reboot your Pi
sudo reboot
After that you should have no problem connecting to your cutter via Carbide Motion (or anything else for that matter).
Credit where credit’s due:
I only know about this bug because I am active in the Voron community (an open source 3D printer design) and this same bug effected those machines as well. Credit goes out to Shiftingtech on the Voron Discord for being the one that provided information this post is based on.