[xiaomi-beryllium] Rootfs issue, boot stucks into busybox shell

Originally filed under droid-juicer, though it came out the fault (if any) isn't there.

The hardware is working, as flashing pmOS on top of the broken system gets to a working state. And I swear Mobian was also working some weeks ago on this same device, then maybe is it a matter of the flashing procedure? But I'm flashing pmOS with the same laptop/port/cable that I use for Mobian...

Following image refers to test done with mobian-qcom-phosh-20240915, IIRC that image was flashing correctly to beryllium in the past