> NOTE: If you have a 2010 model MBP or earlier all you have to do is change the amount of RAM in your MBP and clear the PRAM. This is all you have to do to get past OS lock. But you will still have a firmware lock as far as I know as in many cases this has happened. There have been occasions where the firmware lock has also been removed but I cannot contest to any exact models. Remember to set the Mac up like new and register the Mac with a new iCloud account to avoid any future lock-downs.
> Option A: You can assume that a firmware lock was never set and brute force the firmware lock with a HID device such as a Teensy. This operation can take quite a while because it has to go through 10,000 iterations of possible pass-phrases in the worst case scenario. This will ONLY work if it was set by the iCloud!
> Option B: You can assume that a firmware lock was indeed implicated when the MBP was set up and that the brute force method will not work. This can save you time but requires you to have a SPI programmer at hand such as the Bus Pirate or in this case a Raspberry Pi.
Apple EFI firmware passwords and the SCBO myth
https://news.ycombinator.com/item?id=11974806
https://reverse.put.as/2016/06/25/apple-efi-firmware-passwor...
The site is under heavy load at the moment; here is a cached version:
http://webcache.googleusercontent.com/search?q=cache:https:/...