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820-1987 stuck in DFU Mode

G

grmacs

Member
Prior to putting in DFU this board had liquid damage to LCD backlight area. That was solved and I could see cycling of power rails. I could see .8V on CPU rails cycling power briefly. So I thought maybe T2 issue. Was able to get it in DFU mode and have tried restoring the T2. It gets to 4th step then fans come on high and i get this error:

The operation couldn’t be completed. (AMRestoreErrorDomain error 9 - Failed to receive message from device, might be connection problem with USB host. (Communication error, possibly USB disconnection)) [AMRestoreErrorDomain – 0x9 (9)]

Now it seems to be stuck in DFU all of the time. Now when i plug it to power it stops at 20.4V and 0 amps. Prior it would cycle the wattage and amps but wouldn't boot. I'm not seeing any signs of more issues on the board.
 
G

grmacs

Member
Or i have an old unlock Rom file I think for A2289. I'm thinking that was should be good just no serial number I believe.
 
G

grmacs

Member
Ok. I was able to flash the SOC Rom. It is still stuck in DFU. I tried holding power key down and SMC reset but it doesnt want to exit DFU and get the same error after attempting restore.
 
G

grmacs

Member
Still same error. When I got this Mac it wasn't in DFU but has been apparently once I got it in DFU unable to leave DFU mode.
 
G

grmacs

Member
I can't remember what I did but I resolved the communication 9 error but it is still stuck in DFU but now giving this error when trying to do a restore:

Unexpected device state 'DFU' expected 'Recovery' (Probably forced into DFU mode externally) [com.apple.MobileDevice.MobileRestore – 0xFAE (4014)]

I saw on the boards someone that this error but they found issue on one of SLP2R lines. I did not find a fault. Mine are all good:

PP1V2_AWAKE 1.2V

PP1V8_AWAKE 1.8V

PP3V3_AWAKE 3.3v

PPVDDCPU_AWAKE 0.755v

PPVDDCPUSRAM_AWAKE 0.802v

PP0V8_SLPS2R 0.800v

PP1V8_SLPS2R 1.8v

PP1V25_SLPS2R_SMC_AVREF 1.25v

PP1V1_SLPS2R 1.1v

I think I'm missing SSD lines but isn't that because stuck in DFU or no?
 
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