Device or resource busy

[Jennigma (Jennifer Leigh)]

You are using Ubuntu? We discussed this a couple days ago when I was starting to work through a Linux install for writing up docs. Discussion here:

Feedback requested: simplified software installation

I was using Debian. If you are on Ubuntu, check if you have ModemManager installed, it has a tendency of jumping on each and every serial port, which can easily result in them getting busy. The Kaleidoscope repo has some udev rules you can install, which will prevent ModemManager stealing the keyboard’s serial port. Stick that file in /etc/udev/rules.d, and then sudo udevadm control -R should reload the rules. Plugging the keyboard in afterwards should then work.

Stopping ModemManager may be a bit more extreme than needed; you can follow algernon’s advice to get ModemManager to just ignore the keyboard.