Yeah - but if ums-loader is black screen it's not a good sign - ums-loader runs in IRAM (internal ram inside the CPU).Logically its not a corrupted nand content.
I think its more probable the ram is malfunction.
Since ums-load use only iram.
You might check the connection between the ram and the cpu maybe theres some resistor burned.
Or you could check the supplied voltage to the ram, maybe the voltage is not being supplied.
If the voltage in problem, you might track it, which ic supplied the voltage. Maybe some resistor burned.
Post automatically merged:
Before the glitch happened, theres a write to emmc, and read from emmc.
So we could assume the nand is okay hardware perspective.
I assume the next step is, the cpu will fetch the machine code from the emmc to the ram, then run it.
The bootloader (BCT) in the emmc is modified, and it will run the payload.bin (which is loaded to the ram).
So the most probable scenario is theres problem on ram.
That's why it's a good test - because even if DRAM has a problem ums-loader will still work.
(plus if it runs it can test emmc / backup / restore).