How to Boot a Mac from Firewire

Method 1 of 3:

Locate your Mac computer's FireWire port. It will usually be located near the USB port and will be just a bit narrower and taller than USB ports, with angled corners on one side of the port.
Plug the FireWire connector for your FireWire drive or device into your Macintosh computer's FireWire port.
Hold down the 'Option' key as you power your Macintosh computer up.
Select the FireWire drive from the list of available boot-up options that displays on your Macintosh screen.
Click the right-facing arrow to select the FireWire drive and finish booting your Mac from it.

Method 2 of 3:

Turn your computer on and let it boot completely.
Locate your Macintosh computer's FireWire port, as above.
Connect the FireWire connector for the FireWire drive to your Macintosh computer's FireWire port.
Open a Finder window to make sure that the icon for the FireWire drive is displayed under 'Devices' in the Finder window.
Open the System Preferences dialog for your computer and select 'Startup Disk' from the list of System options.
Select the FireWire drive you want to boot with.
Click 'Restart' to reboot your computer using the FireWire drive.

Method 3 of 3:

To use Macintosh computers as FireWire disks themselves, hold down the 'T' key during system start up. This forces the system into FireWire " target" mode, at which point it can be connected to another Macintosh computer via a FireWire cable and used as a remote (target) drive disk.
- This is a useful technique for transferring specific data from an old computer to a newly purchased computer. Just boot the old computer in target mode, connect it to the new computer, and transfer only the data you want to transfer, instead of transferring everything with the Migrate utility.
- This technique works for almost all Mac computers, in both desktop and notebook models, with G4 or faster processors. The one notable exception to this is the Power Mac G4 model with PCI graphics, which does not support FireWire booting.

The ability to boot a Mac from FireWire is most useful when you're experiencing problems with your Mac and need to run system diagnostics, or simply access the system but cannot do so through the computer itself. Purchase a FireWire flash...