820-01958 dead unable to put into DFU mode

[TBFix]

Hi I got an 820-01958. PPBUS_G3H is 12.6v, PP5V_G3S is 5v, PP3V3_G3H is 3.3v. PVDDCPUAWAKE_SW0 to SW3 are 0.75v, PP0V82_SLPDDR is 0.82v, PP1V8_SLPS2R is 1.8v, , PP1V1_SLPS2R is 1.1v, PP0V9_SLPDDR is 0.9v, PPVCCQ_ANI_SSD0 is 1.8v. PP1V05_PCH_EXT_REG, PPVNN_PCH_EXT_REG, and PPVCC_CPU_PH1 to PH3 are all present when the unit is undergoing a DFU. DFU fails with either 4010, or 4017. We've noticed that Y8001 reads 33-34Khz and increases to 42Khz during a DFU.

I also tried looking for dump of U4770 but am unable to find one. Any input appreciated.

 

[2informaticos]

If machine cannot complete DFU, should be a problem with T2, or SSD.

Any history available, liquid sign?
Check for liquid sign at audio board and flex.

 

[TBFix]

I checked the audio board on the machine, it's perfectly clean. There was some liquid damage from hot chocolate on the board around Q7660 which has been cleared, and near C6481.

 

[TBFix]

Would there be any point in trying a known working dump of the SoC ROM? If so would anyone have one available?

 

[2informaticos]

I don't have SoC ROM dump for this board.
People say on Internet they solved not turning board on Internet on this way.
However, I'm not sure about this.

Personally I swapped a dump from good working 01521 board to other, which turned on too, but had other issue.
Aftewr that, the board didn't even switch to 20V; using tested dump, good 100%.