Firmware Password on Mac OS X

Security goes beyond settings passwords and encrypting data. Mac OS X supports additional methods to secure the system itself. Setting a firmware password helps prevent circumvention of the OS-level security through an unauthorized boot device. Antivirus protection helps insure that any viruses that might come from other operating systems on the network won't threaten your data.

Firmware Password
You can configure a firmware password to enable low-level hardware protection for your Mac. A firmware password helps prevent unauthorized users from booting your Mac from an external hard disk, optical disc, or USB key drive. In order to complete this process you’ll need the Snow Leopard Install DVD.

To set a firmware password:
To set a firmware password, follow these steps:

1 Log in with an administrator account and open the Firmware Password Utility (located on the Mac OS X installation disc in /Applications/Utilities/)or(in recovery under utilities menu).
2 Click the "Require password to change Open Firmware settings" checkbox.
3 Enter a password in the Password and Verify fields.
4 Click OK. A confirmation appears. Click the lock icon to prevent further changes.

You can test your settings by attempting to start up in single-user mode. Restart the Mac while holding down the Command and S keys. If the Mac displays the login window after starting up, changes made by the Firmware Password Utility were successful.

To reset a firmware password:
To reset a lost or forgotten Firmware Password, access to the inside of the Mac is required (just like resetting a PC BIOS password requires removing the on-board battery).
To reset a firmware password, follow these steps::
1 Shut down the Mac.
2 Change the memory configuration by adding or removing RAM.
3 Start up the Mac (This will clear the firmware password).
4 Shut the Mac down again.
5 Return the RAM to its original configuration.
6 Start up the Mac

Note: For information on recovering a lost firmware password on a MacBook Air (Late 2010), refer to http://support.apple.com/kb/TS3554