820-01841 ( ? ) on boot device. Unable to read SSD

[KC Micro Tronix]

I have verified the power rails are present.
unit sill not recognize on board HD.

No shorts, no hot spots, All the SSD rails are normal.

My next option would be to pull NANDs and test.

Question before I start that. Can I replace these? Is there some magic apple drama preventing me from doing so? If I do replace them do I have to read and save some data first to be transferred to the replacement chips.

 

[2informaticos]

T2 firmware partition is on internal SSD.
You will need a DFU restore after that.

Apart of power rails, check SSD signals; as reset, clock.
Compare with good board, if possible.

 

[KC Micro Tronix]

can I just swap them and DFU restore or do I have to copy the nand data first

 

[2informaticos]

I suppose you want to change the BAD chips.
How do you plan to read them?

DFU restore should do the trick with new chips...

 

[KC Micro Tronix]

I have a programmer that can read these chips. I can copy data from one to the other. I use them on A12 and above ipads and such.

 

[2informaticos]

I supposed you want to change some BAD (damaged) chips.
How to read them, if are bad?
If the chips are still good (readable), why need to change them?

 

[KC Micro Tronix]

I can read and write these chips. They are the same as A12 and newer iPads. Have a WL programmer for them

 

[2informaticos]

I understand you have the tools to read these NANDs.
But you've asked about change them in a logic board.
If the chips are good, then why to replace them?
And if the chips are bad, I don't expect you can recover data...