@Rex yeah, can confirm - I’m using the CM4 ROM from the github (GitHub - clockworkpi/uConsole: This code repository offers downloads for the latest images of various uConsole models, along with kernel patches, firmware for the keyboard and 4G expansion module, hardware schematics, assembly instructions, and essential technical documents.)
Just flashed it again, slotted it, power with no boot. I get the R-01 image from the same place, can flash that image back on, swap the boards over, and boot into that one with no problem. I just can’t seem to come over to the CM4.