Dual Boot Apple

Purpose

To dual boot on an Apple machine, for instance between OS X and FreeBSD.

Details

The default EFI boot manager on Apple machines is tuned for working best with OS X installations. What a surprise. In order to take advantage of the overpriced hardware at your disposal, yet from another operating system (let it be a GNU/Linux distro, one of the *BSD, or even Microsoft Windows), it is necessary to modify the partition table of your drive, as well as installing a more powerful boot manager. Once this is done, the installation process of one or several other operating system will vary depending the selected OS. Eventually you will be able to choose at boot time which OS you want to load.

Step by Step Recipe

• We start assuming that your OS X installation is one single partition on an internal or external drive;
• Install rEFInd boot manager
• Start Disk Utility and resize the OS X partition to give enough room for the extra OS (for the record Mavericks needs at least 8GB, so reducing the OS X partition to 20GB should be enough for a basic install and a couple of closed source bloatware, however the Disk Utility may prevent you to limit the space that much depending on the drive specs and your current configuration);

Troubleshooting

If you can't get back into OS X because you blessed the wrong partition or you managed to make a mess of GPT, you can always try the following: boot the machine, after the chime press the alt until you see a list of available OS X partitions that can be booted.