Faulty USB/Serial - USB disconnection issues

[CooperGerman]

Hi I'd like to write this here for posterity.

I've been successfully printing with my mk3s under klipper for 2 months now but started having

Transition to shutdown state: MCU 'mcu' shutdown: Timer too close
This often indicates the host computer is overloaded. Check
for other processes consuming excessive CPU time, high swap
usage, disk errors, overheating, unstable voltage, or
similar system problems on the host computer.

After a while i found that the the problem was originating from a faulty firmware in the USB/serial chip on the einsy bord and had to follow the steps in https://github.com/PrusaOwners/mk3-32u2-firmware in order to fix it.

Symptoms are :

• The above message in the klippy.log file (or mainsail/fluidd view)
• print stopping after several hours when long prints are launched
• High number of invalid bytes (Stats 1146925.7: gcodein=0 ... bytes_write=30281567 bytes_read=11930587 bytes_retransmit=382965 bytes_invalid=**986474** ... in klippy log)

Feel free to include this in your documentation if needed.
Thx for your great work.