I had the same problem when running the script after doing CR50 - and now that I think about it that could be why I can’t recognize the drive after manually flashing rom (via SuzyQ /w flashrom) externally.
@MrChromebox - YAVIKS is using UFS instead of eMMC and is showing up as sda12 (erroring out on the script)
On the coreboot side - i was able to get CBMEM from a windows live bootable:
[INFO ] PCI 12.7, PIN C, using IRQ #22
and
[INFO ] PCI: Static device PCI: 00:12.7 not found, disabling it.
see related post