[Help] Tab10CPro won’t boot after TabUltraC Pro cross-flash — rollback block

[LingJing]

Hi everyone,

I’m trying to recover a Chinese BOOX Tab10CPro after attempting to convert it to the international Tab Ultra C Pro firmware.

My situation:

Original device: BOOX Tab10CPro (Chinese version)

Original/latest Chinese firmware: 4.2.1, Build 11817

Target firmware: Tab Ultra C Pro international firmware

EDL/Firehose access still works

Stock recovery is accessible

The stock fastboot implementation does not support flashing

I extracted the images from the Tab Ultra C Pro firmware and wrote the corresponding partitions through EDL. Unfortunately, the device does not boot normally after the conversion.

I then tried to restore the latest official Tab10CPro firmware through recovery. Recovery refuses to install it because the timestamp/build date of the Tab Ultra C Pro firmware currently recorded on the device is newer than the latest available Tab10CPro firmware. It is therefore treated as a downgrade.

Where is the timestamp/downgrade check stored or performed?
Or what partitions are required for a complete Tab10CPro-to-Tab Ultra C Pro conversion?

[LingJing]

Update Package is older than current build
expected a build newer than timestamp 1786442463 but backage has timestamp 1786441785 and downgrade not allowed