@G30FF

Thank you my friend. You saved me a bunch of wasted time. I would have had to dig deep since I did not see this documented when I read the specs.

I found this and got it installed. =)
https://www.jeffgeerling.com/blog/2020/how-flash-raspberry-pi-os-compute-module-4-emmc-usbboot

@mitu

I need this Board to put it into a small formfactor 3d-printed AES Case and run Retropie with only Neo Geo Games. This board has all the connections i need at one side. it´s perfect.