Any Leopard-compatible Macintosh is capable of setting a hardware password, using OpenFirmware for PowerPCs or Extensible Firmware Interface (EFI) for Intel-based machines. When enabled, hardware password protection blocks the ability to do the following:
– Use the C key to start up from an optical disc.
– Use the N key to start up from a NetBoot server.
– Use the T key to start up in Target Disk Mode (on computers that offer this feature).
– Use the D key to start up from the Diagnostic volume of the Install DVD (Intel only).
– Start up a system in single-user mode by pressing the Command-S key combination during startup.
– Reset the parameter RAM (PRAM) by pressing the Command-Option-P-R key combination during startup.
– Start up in verbose mode by pressing the Command-V key combination during startup.
– Start up in Safe Boot mode by pressing the Shift key during startup.
In addition, hardware password protection requires the password to use the Startup Manager, accessed by pressing the Option key during startup.
To enable a hardware password, start from the Leopard installation DVD and choose Utilities > Firmware Password Utility. Select the option to “Require password to change Open Firmware settings”; then type and verify the password, and click OK. You can disable a forgotten hardware password by powering down the hardware, changing the RAM configuration (for example, removing 2 GB from a 4 GB machine), and rebooting. This procedure works for all Macintosh machines except the first-generation MacBook Air, which contains no user-serviceable RAM (the chips are soldered to the motherboard). If you forget a hardware password for a MacBook Air, contact your local Apple authorized service center.