When I tried booting into recovery mode (Cmd ⌘ + R) during boot up, there's a field asking for a password. I do not know this password.

Password Screen

I am using a late-2009 21.5" iMac.

Anyone know what to do?

  • So, is there someone who set the firmware password on that machine? Ask them... Or you are the only user, and somehow did it yourself accidentally?
    – GEdgar
    Jun 26, 2013 at 16:13
  • I faintly remember doing it ages ago but I guess I forgot it. The password was definitely one of mine.
    – moka
    Jun 26, 2013 at 19:52

2 Answers 2


From the image, it looks like a Firmware password.

This bash script may be able to decrypt your firmware password, however it only works on a limited set of computers.

python -c "print ''.join(chr(int(c, 16) ^ 170) for c in '`sudo nvram security-password`'.split('%')[1:])"


  • Hey! Thanks very much for the help. I already decrypted the password and managed to get into recovery mode using the tutorial here: reviews.cnet.com/8301-13727_7-57521667-263/…. Thanks again!
    – moka
    Jun 26, 2013 at 17:56
  • @moka No problem :D You do realise that was the same link that I put in my post ;)
    – grg
    Jun 26, 2013 at 18:01
  • Oh haha sorry, I didn't check the source link. Thanks again for the help. :)
    – moka
    Jun 26, 2013 at 19:52

If your mac is pre 2011 then removing a strip of ram and rebooting will clear the problem. I have done this with quite a few that I have installed new systems onto and it seems to work very well. Give it a try, what have you got to lose.

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