Mele A2000 custom firmware failure... found

The box opening is painless (4 screws under, 2 at the rear - all the same type):

OK, wired the serial TTL-to-USB line, only GND, Rx, Tx, paying attention to cross Rx/Tx lines:

And during the flash operation of my custom image, the last log lines are:

[     130.560] normal type verify
[     131.130] pc sum=0x17135c9f, check sum=0x17135c9f
[     131.130] dl name = sysrecovery
[     131.132] img size = 305738752
[     131.136] part size = 536870912
[     131.139] read start=34816
[     131.142] write start=4630528
[     203.602] dl name = UDISK
[     203.603] sprite update error: fail to open part file DISKFS_000000000
[     203.633] sprite update error: current card sprite failed
[     203.640] now hold the machine

OK, missing UDISK (filename DISKFS_000000000)

Indeed, it does not appear in files/image.cfg from the a10_flash_kitchen_v2/packer_ics directory.

Now I need to repair that.
To be continued...