820-00928 Sporadic SSD detection

[macfixer]

Hello friends,

I have a macbook here that the customer ran an update on, after this, the macbook started to become hard to boot, only booted sometimes.
When i started troubleshooting i couldnt get it into system at all.

Data very important

Things tested:
Safe mode several times: boots to blinking question mark folder after loading for ~3 minutes
DFU revive several times: errors every time you try to revive
Replaced the bridge piece that goes on J9600 twice

Target mode works temporarily, once you click on the disk in disk utility on the host machine the entire host machine hangs and stops responding, needing a restart to work again. If you avoid clicking on the disk in disk utility and instead try to directly clone the disk it unmounts itself.

I have attached diode mode readings of J9600, "left side" is left when SW5200 is to the right of J9600

 

[2informaticos]

J9600 should be good, if SSD is detected in Target Disk mode.
Check for corrosion around NAND chips; some resistors, or caps may be affected.

What kind of DFU did you try on A1707?
This is not T2 machine...

You can try known good BIOS, just in case.
Bout I doubt will help.

 

[macfixer]

Checked everything under NAND shields, no signs of any damage, corrosion or similar

I keep confusing DFU and T1/T2, sorry about that

Will test bios

Edit: the diode values i got are very different from openboarddata.org values, you think its fine?

 

[macfixer]

The middle NAND on left side seems to get significantly hotter than the rest, not sure if its unusual

 

[macfixer]

Ive noticed something new, when the macbook is booted (it seems to only like targetmode in the chassi), the CPU is making a lot of noise when thunderbolt cable is plugged in, once you pull it out it stops making the noise, perhaps its an issue with a controller rather than NAND? Im not really sure
See attached video link (increase volume to max to hear the noise)

IMG_0210

Watch "IMG_0210" on Streamable.

streamable.com

 

[2informaticos]

I suspect the heater NAND to be the culprit.
Trying with dedicated data recovery tool can confirm if the problem is SSD itself.