A1708 EFI UNLOCK, MACHINE UNBALE TO POWER ON

[DAN LI]

I brought a DS-809E to unlock some A1708 that we have aquired.

After following some of the steps found in youtube, I was able to extract the .bin file and using a hex editor to remove the password.

But after rewriting the .bin file back, the macbook wasnt able to switch on, no fan movement. I even try rewriting the original .bin file back, but the machine remaind dead

What did I do wrong? Can someone help me?

I have attached the original bin file

[mon2]

Suggest to seek out a known good flash image to apply onto your flash device. Verify that the contents match. Are you using the original flash memory chip? If not, test with the QE (quad mode) bit set to ‘1'. This enables QSPI mode.

Do you have a usb type C meter? Available on Amazon and AliExpress stores.

What is the voltage and current draw?

Are you using a suitable power adapter? Recommend 100W with a proper active type C cable that can support 100 W power delivery contracts. This demands the e-marker chip inside the cable hood.

What is the voltage to ground of ppbus_g3h ?

Do test the other side of the usb-c blade connector by rotating the power adapter head by 180 degrees.

https://repair.wiki/w/MacBook_Pro_A1708

[DAN LI]

The macbook was able to be turn on without any issue before i started the EFI unlocked, i used the same set of adapter.

I didnt change anything like the memory chip or battery.

Here is the attached pic of the USB Type C Meter


Sorry I jyst started my journey unlocking and repairing macbook so I am unsure what are the steps you mention.

How do I mesaure the voltage to ground of ppbus_g3h ?

Thanks for replying

This is the 3rd A1708 i brick this month using EFI unlock

[mon2]

Do you see a gradual increase of the current draw or is it a fixed value? 20v is good. Current draw looks normal.

Do you have a led toggle when pressing the caps key? If yes, the logic board has booted. Apply a flashlight to the front side of the display to check if you have any graphics.

[DAN LI]

I take a video of the meter,

The fan does spin a while when I first plug the charger in, but stops a while later.

The logic board doesnt seems to booted as the fan stop spinning and no light on caps key

[mon2]

Disconnect the battery and trackpad. Test again.

[DAN LI]

After disconnecting the battery and trackpad, the fan can start up but still no display and caps no power

[mon2]

The trackpad cable appears to be defective. Test with another. Without the trackpad connected, the cpu will slow down since the thermal sensors in the trackpad are absent.

What is the 820-**** number of your logic board?

Test the attached bios (from Rossmann group forum). https://www.badcaps.net/forum/troubl...n-me-pram-bios

[DAN LI]

the logic board number is 820-00840

okay before I test, but the macbook is able to boot up multiple times and show me efi lock before i use the ds809. how did you know its defective? what the telltale sign?

[DAN LI]

Test the attached bios (from Rossmann group forum). https://www.badcaps.net/forum/troubl...n-me-pram-bios

This solved my problem, thank you man. I connected the trackpad and battery both are working fine too