A1502 Macbook Pro EFI general question regarding serial number

cobragfox

Member
What happens if I flash an EFI chip with a serial number that's not the original? My issue is, I needed to replace the EFI chip, but the serial number on the chip didn't match whats on the bottom cover. The customer said he had the bottom cover replaced, hence the difference in serial number.

Well, when i flash the chip with the serial number from the original chip, the comp. never boots, (i do have all voltages present and cpu warm). When i flashed the chip with the serial number on the bottom cover, i'm able to boot the laptop successfully and log into it.
 

dukefawks

Administrator
You cannot just flash another BIOS it will mess up the ME region. Upload the BIOS here and specify the serial number you want and I can make a known good BIOS for you.
 

cobragfox

Member
I did use ghostlyhaks steps to set a clean ME region. But for some reason when i do it with the original serial number (which was pulled from the computers EFI chip) the computer never boots. Only when i use the serial number on the bottom cover, which isn't the original bottom cover (bottom cover was replaced recently), this is when i'm able to get it to boot.

Anyway, i've added a link to the file as i wasn't able to upload the .bin file. Thank you so much for your help.

https://drive.google.com/open?id=1LD0HKiIGDaDTnX5vp-kb2uc1lTYMrSs9

Serial number is: C02PVZ3GFVH3
This is the same serial number in the attached bios dump.

Again thanks a lot.
 

cobragfox

Member
Yep this worked. Just curious what I was doing wrong. Does the bios I’m modifying have to be unlocked to modify and if so, how does one find an unlocked bios?
Or do I copy the bios data (except the ME region) from my locked bios and paste into the clean unlocked ME file?
 

dukefawks

Administrator
I cleaned the ME region and took a known good BIOS and pasted your serial number into that. Then the checksum of the Fsys block that contains the serial number was corrected.

I can write a book about this or you can just buy the Medusa2 at cmizapper.com and that will do this for you.
 

Bouba148

New member
Someone does know how to use the dip switches on the medusa 2 because i've not received any documentation or link where to download it.

Thanks
 

Bouba148

New member
thanks for replying, this is exactly what I did without knowing it......thanks
but the thing now it's 1:20 am in europe and no one will answer me .....maybe even not before monday......if they don't work tomorow.
I've checked some of their videos on Youtube but just got the info for read and verify modes.
I'd like to try the others, especialy the Clean ME mode.
 

Bouba148

New member
Big thanks to you MacRepairAmb.

As I've tryed them all in the mean time, then I can complete the list:
26: Show Medusa internal ROM 2 and 3
27: Load Medusa Internal ROM
28: Show Medusa ROM 3 ME Version
29: Verify ROM 3 in Medusa
30: TEST POWER
above it's just ?????????

Question when it's reading the Mac serial number of 2 differents 00165 board it's written BAD next to it WHY?
 
Checksum is bad. That’s why you will get a “bad” messiahs by the serial number. First read and store your current efi bios. The perform mode 12. But make sure you backup the efi data before you proceed.
 
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