820-01061-A

[Anterweb]

Have this Imac in for EFI removal.

Just opened it up but dont see a Jtag connector. Can this be done using the Medusa? if so, how?

 

[2informaticos]

Need to remove the SPI chip.
You can clean it with Medusa then, or use one of these files.

iMac A1418 820-01061-A.rar

drive.google.com

01061 outimage new.bin

drive.google.com

Let me know if any good.

Don't forget to fix checksum, if change the serial number.

 

[Anterweb]

Ah OK thanks, you wouldn't have a schematic for this board? I can't find one anywhere?

 

[2informaticos]

820-00597 may help you a bit.

 

[Anterweb]

Just booted this up to test it before removing the bios chip, first thing I see is Internet recovery screen, it asks for network connection then loads into the screenshot above.

Is this something a fresh bios will fix? I haven't seen this before?

 

[2informaticos]

Tried PRAM reset?

 

[Anterweb]

It won't let me reset pram, no matter what I do on the keyboard I've tried keyboard in all USB ports, it just boots streight into choose network with spinning globe recovery screen,

I'd promised this customer he could collect today thinking it would be a 10 minute job with medusa, is this something more than just a bios swap, should I put him off for a couple of days?

 

[2informaticos]

Did you try both files I sent you?
If you can't access boot menu, nor do PRAM reset, EFI password is still present.

 

[Anterweb]

No I haven't removed the spi chip yet, I wanted to be sure I could fix it before I removed the chip. I'm going to do it shortly.

Also, can I just edit the serial number in the bios programmer software or do I need a hex editor, I've never had to change this before, and you also mention fix checksum, how is this done please?

 

[2informaticos]

Is all explained on the forum already.
Also videos available on Internet.
Changing serial number without fixing checksum can create weird issues.

You can just copy/paste entire Fsys region from your BIOS backup and replace into the new file.
Then no need to fix anything more.

 

[Anterweb]

Just spoke to the customer and he said he isn't bothered about serial numbers, so am o OK to just dump the the bios you gave me here and reinstall os and give it back?

 

[2informaticos]

Ttry and see first if files are good.

Don't forget to make the backup; upload it somewhere, just in case.

 

[Anterweb]

This mac has now been collected without getting the chance to try the bios files. (he is going away)

Sorry Inf..

 

[2informaticos]

Pufff, I was expecting backup to clean EFI password, without changing anything else on the original BIOS.