Customer comes in with a story. Child put EFI firmware password on his Macbook Air.
Nobody knows the password.
My first thought; (this is a red flag, code for STOLEN. – Or a sting. Not worth it).
Being curious – I asked him if he knows the user account password and if he could log into the account once I get it to boot. He had it on his phone. I copied that. We can remove, change that user account password, as well…much more easily…but here, it serves good purpose.
the ugly part
I photocopied his driver’s license and had him sign a statement that he is the rightful owner of the MacBook (serial number).
This is the EFI firmware (BIOS) lock in action.
Makes an otherwise fine device rather useless, that lock thingie there, no?.
On to the job at hand.
I removed the BIOS chip from off of the MacBook’s board, soldered it onto an adapter card on my programmer and copied the .bin file from off of the chip onto my workstation.
I then made copies of that file. I edited a copy of the file with hex editor, removing area of code that is the password. Saved edited file, flashed that onto the chip…
Re-soldered the chip back into his MacBook…reset NVRAM; It booted quick and perfect!
Password for the user account worked. Everybody is happy. A MacBook may not make the best babysitter? Didn’t hurt ME none. – just sayin’