Mac OS X Hacks

Using Open Firmware Password Protection

Password-protect your Mac, blocking circumvention by booting from another device, booting into single-user mode, and more.

There are times when you want nary a finger but your own fiddling with your computer. No sister, no boss, no mother looking for porn, no husband reading chat logs. With the Open Firmware built into newer models of the Mac (iBooks, G4s, some iMacs, etc.), you have access to a strong, low-level way of password protecting your Mac from meddling interlopers and innocent wanderers.

Before we go any further, you’ll have to check whether your computer has the necessary firmware. To do so, open the Apple System Profiler (under /Applications/Utilities/) and look under the System Overview section for the Boot ROM version (which also represents your Open Firmware version), as shown in Figure 2-3. On my dual 450MHz G4 running 10.2.2, you can see Boot ROM info with a value of 4.2.8f1. To be eligible for password protection, you’ll need later than 4.1.7 or 4.1.8 (firmware upgrades are available at Apple’s web site).

Figure 2-3. Apple System Profiler

Once we’ve met the version prerequisites, what exactly does this password protection prevent? Longtime users of the Mac OS may recall such pre-OS X hacks as holding down the Shift key or customizing your extensions with the spacebar, as well as the ability to boot from a CD. While extensions ...