The PSU holder is my own design, very close to the one for the Basic Board. You can use it as additional PSU holder when you want to operate a RasperryPI and don't want to take the fuel out of the PSU form your printer. Start up of a Pi needs 3A on 5 Volts… so that might be critical depending on the load/reserve on your printer PSU. Sure the you need a DC/DC down step converter as well…. with the additional PSU holder that issue is fixed :-)
To mount the ferrit of the cable…. i used this one from MichaleQ:
https://www.printables.com/de/model/544680-original-prusa-enclosure-ferrite-core-mount-for-ba
The author marked this model as their own original creation.