Schematics
See Hardware Schematics
Please note V01 means V0.1. V02 means V0.2. V1 means V1.0.
Raspberry Pi Compute Module 4 IO Board
USB ROM Boot
To enable USB ROM boot, short or fit a jumper on the J2 header pins marked as “Fit jumper to disable eMMC Boot”. This will force the board to enter USB ROM boot.
UART Serial Debug
See UART Serial Debug Guide