820-01700 data recovery

[Kyle93]

Trying to attempt a data recovery a 820-01700 board. The original board had a deep internal short on PPBUS_G3h but SSD power rails were not shorted.

I transplanted the T2 chip T2 rom and all of the NANDs to a working board. During DFU revive the first two attempts the screen came on with apple
Logo and progress bar but always failed with DFU error 9.

When trying to do a DFU revive now the fans spin normally for several seconds but then suddenly spin very fast and nothing ever comes up on the screen now ending with the same DFU error 9.

Is there anything else to check or try or is it more likely one of the NANDs is bad now and data is not recoverable

 

[2informaticos]

Test if you can complete DFU with original NANDs; from working board.
If yes, then you have a bad NAND.
If not possible, then possibly bad T2.

Just in case, try first DFU as actually is, erasing U4770.

 

[Kyle93]

What do you mean by try first DFU as actually is? Should a different U4770 be used? Can the data on NANDs still be recovered if original U4770 is erased?

 

[Kyle93]

If original NANDS from working board are put back but the transplanted T2 stays on the board and a dfu restore is performed can this compromise the ability being able to get the data from the other NANDS since T2 tied to data NANDs is used for the restore test ?

 

[2informaticos]

SSD encryption key is stored in T2.
If you change the NANDs, T2 maintains the same key.