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  • How to Enable Mac OSx Firmware Password Protection

    Warning: Altering your Open Firmware configuration in a manner that is not explicitly endorsed by Apple may damage your machine's logic board. Repair's for issues created by these unsupported configuration changes are not covered under the terms of any of the Apple support agreements.

    Warning: Please reselect your startup device PRIOR to resetting your PRAM or Open firmware.

    The following firmware configuration is supported on:

    • All Intel-Based Macintosh Computers
    • iMac (Slot Loading) and later models of G3 iMac
    • iMac (Flat Panel) and later models of G4 iMac
    • iMac G5 and later models of G5 iMac
    • iBook – all models, both G3- and G4-based
    • eMac – all models
    • PowerBook (FireWire)
    • PowerBook G4 and later models of G4 PowerBook
    • Power Mac G4 (AGP Graphics) and later models of G4 Power Mac
    • Power Mac G4 Cube – all models
    • Power Mac G5 and later models of G5 Power MacHow to Enable Mac OSx Firmware Password Protection

    Open Firmware password protection disables the following features:

    • Depressed N-key boot – Boot from NetBoot server
    • Depressed T-key boot – Boot in Target Disk Mode
    • Depressed C-key boot – Boot from CD/DVD or other designated optical drive
    • Command V boot – Boot in Verbose Mode
    • Command S boot – Boot Single User Mode
    • Command+Option-P-R Combination boot – PRAM Reset
    • Command+Option-O-F Combination boot – Use of Open Firmware Interface commands without a password. – Not available on Intel-based Macs
    • Option key boot – Use of Startup Manager without a password

    Enabling the Open Firmware Password

    Obtaining the Software

    Mac OS X 10.4 and higher

    Download the Open Firmware Password Application from here: Open Firmware Password.

    Mac OS X 10.1 – 10.3.9

    The Open Firmware Password Application Utility is located in the /Applications/Utilities/ folder on your software installation DVD. Please copy it to your machine.


    1. Launch the Open Firmware Password Application.
    2. Click the authentication icon and enter your Administrator credentials. You will be prompted for a password.
    3. Locate and click the Change button.
    4. This will launch an Open Firmware Password window.
    5. In the Open Firmware Password window, locate and click to select/check the "Require password to change Open Firmware settings" option.
    6. Enter your Administrator password.
    7. Retype your Administrator password in the box entitled Verify.
    8. Click the OK button to commit your password and password verification information. This will prompt a confirmation window.
    9. Locate and re-select the lock icon.

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