Hello Nicolas, sorry for the late reaction. I somehow did not receive your last mail, and also was on vacation.
Are you sure you have set up nqc to connect using USB?
Either:
nqc -Susb -firmware firm0332.lgo
Or:
export RCX_PORT=usb nqc -firmware firm0332.lgo
I did use RCX_PORT=/dev/usb/legousbtower0 but with RCX_PORT=usb it did work! (I think I did try this at some point, but alas) Thanks for the help! We have 6 units and can now start using them again in a few student projects. Regards, Sietse