Unresponsive A2337 MacBook Air 820-02016

[sekidata]

This A2337 M1 Air shows no obvious logic board damage but is unresponsive.

Without a battery connected, USB-C goes to 20V, then goes blank, then cycles. PPBUS_AON cycles between 12.0 and 12.3V. With a good battery connected, PPBUS_AON is steady at 12.55V. Trackpad clicks intermittently.

DFU Restore results in the Apple display on the target machine (but no progress bar). Eventually, the display goes blank and the process ends in error 9 (Failed to receive message from device).

I’m still new to the M1+ architecture. Any thoughts?

 

[2informaticos]

Try reflashing U1970.
Be aware DFU restore is required then; it will erase SSD!
You can also test erasing U1970.

If data is important, an authorized service can try to recover it in DFU mode.
Not sure if is still possible.

 

[sekidata]

Ok. Can you point me to a clean copy of the U1970 SoC ROM file?

 

[2informaticos]

"You can also test erasing U1970."

I don't have any dump for such board.
Don't forget to make backup first!

 

[sekidata]

I just used the U1970 from a working board to make a dump of the ROM. Is there a specific place to deposit this file so others can find it?

 

[2informaticos]

Upload on your Google Drive and post the link...

 

[sekidata]

A2337 820-02016 SoC ROM dump

 

[sekidata]

Reflashing the SoC unfortunately did not improve things for this MacBook. I also tried erasing the ROM. No matter which SoC ROM I load, the DFU Restore always ends in the communication error 9.

 

[sekidata]

Does this point to an unrepairable flaw in the T2 itself or would you keep looking?

 

[2informaticos]

DFU Mode Restore (Macs) - LogiWiki

We have Apple MacBook and iPhone Diode readings and general fault finding information compiled by the leaders in this area

logi.wiki

You have M1 machine, but same considerations like T2 apply.

 

[sekidata]

Thanks, that's a great resource.

I tried erasing the ROM again, but half-way through the DFU Restore process, the machine kicks itself out of DFU mode, then back in (this is presumably what causes the communication error 9). I checked and the T2 is getting power, as well as the NANDs.

The console log for MacUpdater shows this:

[17:34:54.2151] Started checkpoint id: 0x60E (update_NAND_firmware)
[17:34:54.2153] <Restore Device 0x7f92f9a5c870>: operation 58 progress -1
[17:34:55.3875] RestoreOS mode device disconnected
[17:34:55.3875] RestoreOS device removed before restored completed

Would you agree that the NAND is the culprit?

 

[2informaticos]

You can try changing the NANDs...

 

[sekidata]

Would they need to be from the same model?

 

[2informaticos]

M1 NANDs don't require pre-intialization, like for T2 boards.

 

[sekidata]

So they could be from an older T2 board?

 

[sekidata]

After installing the NAND chips from an identical 820-02016 board, I now get a new, undocumented error during DFU restore: error 2006.

 

[2informaticos]

The machine appeared into DFU, or Recovery in AC2?
Force it into DFU, if needed.

 

[sekidata]

Yes, I forced it into DFU mode using the jumper method. The error above appears during Restore.

 

[2informaticos]

Try flashing dump from working machine.
Matbe M1 doesn't like empty bin...

 

[sekidata]

Tried that, same result. It's time to say goodbye to this board.