the sd card linked here is known to work without the eeprom edit. it’s the one i used and others have had success too with it.
you can also flash a updated bootloader for the cm5 using rpi imager and try and update the bootloader and eeprom that might help it work better for the first boot. you might have the same problem getting the bootloader updated though if it can’t read your sd card.
the one linked though should get you booted.
1 Like