I purchased a MacBook Air from someone 4 months ago and everything was working perfectly. There is no user name or password needed to log in and I've never had problems using it.

Now I would like to reinstall OS X but I can't do it because it's asking for a firmware password when booting with Option ⌥ held down. It's 4 months now and I've lost the seller's phone number to ask for password.

I've tried to reset NVRM but those keys are disabled. I can't boot from external HD when I turn on the system. What is the reset procedure?

  • 1
    You bought it from a reseller or second-hand? – duci9y Sep 5 '12 at 15:37

To reset the firmware password it looks like you have to take it in for service at your nearest Apple Support location as noted in the following Apple Support Article MacBook Air (Late 2010) and later, MacBook Pro (Early 2011) and later, iMac (Mid 2011) and later, Mac mini (Mid 2011): Recovering a lost firmware password


Learn what to do if you no longer remember the firmware password that you've set or if you see a password dialog when you try to select a startup volume on a MacBook Air (Late 2010) and later, MacBook Pro (Early 2011) and later, iMac (Mid 2011) and later, or Mac mini (Mid 2011) computer.


Only Apple retail stores or Apple Authorized Service Providers can unlock these computers protected by a firmware password.

If you cannot remember the firmware password for your Mac, schedule a service appointment with either an Apple Retail Store or an Apple Authorized Service Provider. If you plan to visit an Apple Retail store, please make a reservation at the Genius Bar using http://www.apple.com/retail/geniusbar/ (available in some countries only).

As a side note you will need the original proof of purchase.


The only way to reset the open firmware password is to take the Air to an Apple store or other authorised Mac reseller.

see: How do Apple engineers reset EFI password on new MacBooks?


If you are ALREADY LOGGED IN AS ADMINISTRATOR FROM WITHIN OSX (meaning, that the computer boots to OSX normally, but you get a firmware lock dialogue when trying any EFI startup hotkeys, which is usually always the case in the Airs I've unlocked for folks) you can spotlight "Startup Disk" or navigate to it from Settings.app and you can CHANGE THE STARTUP DISK FROM WITHIN OSX. I apologize if I was not clear or concise enough with my previous post; hopefully this clarifies the instructions.

You will have to trust me on this one, I've done it before many, many times. (unfortunately)

  • Please edit your previous answer instead of posting a new one – grg Feb 17 '14 at 21:06

Don't reset it. If you have admin access to the computer's OS X install, just change the startup volume to an external USB with the full OS X installer on it. Mavericks is free from the App Store and you just need to download the installer, mount it or show package contents, copy the .dmg file to desktop, burn it to a USB stick in Disk Utility. It's a simple process. Then start disk.app and change to the USB, then reinstall OS X.

After you reinstall, open Terminal and write a shell command to use the Unix setregproptool (it's inside the firmware password utility.app contents located in the installer image and also on the recovery partition) and remove the password by calling the remove password command. The program will ask for the previous password over and over until you get it right, without any delay. So, you can easily brute force it. Most likely its a 4-digit pin, 6-digit pin, or 4-8 character password. If it was locked from iOS, (app or online) it's 4-digits. If it was locked from a computer or non-Apple mobile device, it's a 6-digit pin, and if it was locked manually, it is a password. I believe it's 12 characters max, but don't quote me on it. Should only take a couple of days at most.

  • You still need the password to boot from the USB! – Rene Larsen Nov 13 '13 at 23:34

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