Macbook Air A1932 820-01521-A No boot, 20V it goes to 0.45A then power cycling

[PACh]

LPC bus is not used anymore now.
The corresponding PCH lines are now used as SPI bus, between T2 and PCH.

CPU core voltage is dinamically adjusted.
PCH, CPU and BIOS (T2) are involved there.
And BIOS can only be (automatically) reflashed in DFU

Hmmmm sounds really easy....

One more thing, I noticed that L7030 is 1.9Mohm / 0.455 on diode mode, isnt that kind of low?

 

[2informaticos]

L7030 is not in the same position as old boards.
Don't use it as refference, unless you find short to ground there.

 

[PACh]

tried to do DFU many times, the step 4 takes a longtime after that it goes to the lockpad icon with a warning at the botton saying the system has not booted or something like that and the system needs to be repaired if I try to repair it fails saying that in this state it cannot be repaired so I do DFU again and happens the same...

 

[2informaticos]

Reflash U4770 and try DFU again.

 

[PACh]

Desoldering the chip I lost the 20ohm resistor on the left side R4773 (SPI_SOCROM_MISO Line), I dont have a 20ohm resistor I got a 22ohm same specs, can I use it?

 

[2informaticos]

Yeah, sure.

 

[PACh]

tried all and nothing worked, I think I will just mark it as no fix... Thank you for your help