(347) 552-2258 help@rossmanngroup.com

820-00281 EFi Padlock remove

K

Kappy

Member
I've got an A1707 820-00281 which shows a padlock when option key is press. I've read the BIOS and replaced all contents between $SVS with FF. When i try and boot the MacBook it still shows the padlock, when i read the BIOS again all the information between $SVS has returned.

I tried to replace it again and after writing the data back to the chip, i checked that all the contents had gone, and it had, but it's still showing the padlock sign.

I can't get it to do a PRAM (4 key combo keys on start) but it will do an SMC reset. When i load to recovery, it's waiting for the 6 digit number to be entered and locks after 3 attempts with a 60 minute waiting time.

What am i doing wrong? is there a different method with the A1707.
 
2informaticos

2informaticos

Administrator
Staff member
You've probably forgot to erase the SSD.

The notes from Dukefawks:
"There are 2 instances of $SVS in the binary. One will have a bunch of crap after it and the other won't.
Make the one that has a bunch of crap look like the one that doesn't.
Make sure you keep an original copy in the case you screw up!
After the fix do a PRAM reset and install new OSX!"
 
K

Kappy

Member
Yes, that is basically what I've been doing in the past but i cannot install/erase SSD or do a PRAM reset. I just wanted to check if there was a different method for the A1707
 
K

Kappy

Member
I don't have Medusa programmer, tried to do a PRAM with brand new keyboard, still the same.

I think the reason why it's not allowing it to do a PRAM is because as soon as the MacBook boots it writes the data between $SVS preventing it from allow to do a PRAM.

Not sure at this stage if iCloud/Activation is on or if it would interfere with the lock as it doesn't allow me to get to the stage of checking.

Anything else i could try?
 
K

Kappy

Member
Finally got it to work. To recap the problem when changing the values between the $SVS to FF after starting the Macbook it would re-write the values back, hence not allowing you to do a PRAM as the lock was back.

So i found another BIOS from a donor board which didn't have any lock on it and copied the values between $SVS and bingo it worked. It removed the lock and allowed me to install a fresh copy of the OS.

I don't know if it's just because this is an A1707 or the SSD was blank with no OS on it. ( not sure how that happened)

Anyway this might be helpful for others who are struggling to get the lock removed.
 
2informaticos

2informaticos

Administrator
Staff member
"the problem when changing the values between the $SVS to FF"
Didn't do what Dukefawks said???
You must copy the clean $SVS...
 
K

Kappy

Member
Dukefawks says

"There are 2 instances of $SVS in the binary. One will have a bunch of crap after it and the other won't.
Make the one that has a bunch of crap look like the one that doesn't.
Make sure you keep an original copy in the case you screw up!
After the fix do a PRAM reset and install new OSX!"

What he means is

bunch of crap = hex digits aka locked data
one that doesn't = FF

Basically replace the 'bunch of crap' with 'FF' which is what i've always done in the past, and it's worked fine. In this instance, after replacing the hext digits with 'FF', the 'bunch of crap' is added by the system when you power on the Macbook. So to get round this problem i added the 'bunch of crap' from a non-locked donor a1707 macbook.
 
You must log in or register to reply here.
Top