It's also possible to boot wheezy installers from a USB key in this manner.

You must use OS X's 'bless' utility to change NVRAM entries allowing this to boot. This gives the option of installing rEFIt (or other EFI bootloaders?) on a USB key. To enter the builtin boot menu, hold the 'Option' key while booting. In consideration of all of the above, updating the computer's firmware is the simplest way to easily install and boot Linux and also get 2D/3D graphics acceleration. Booting in the BIOS compatibility mode also means using either the LILO or GRUB bootloaders, and having an MBR partition table (either hybrid GPT/MBR or plain MBR). Without it, you only get unaccelerated frame buffer graphics. This is because the X.org / XFree86 drivers for Intel and ATI, as well as the Linux text console, rely on the Video BIOS and Apple's firmware only provides a Video BIOS when booting in BIOS compatibility mode. In addition, if you want good graphics support in Linux, you must boot it using the BIOS compatibility mode. Recent firmware adds a BIOS compatibility mode, including detection of BIOS-bootable disks and CDs in the built-in boot volume chooser. This is important - some older versions of firmware won't provide some of the underlying support that you'll likely need to install Debian. Verify that your computer has the latest firmware. macmini2,1 installation specials and pain.

Mac mini mid 2010 bios update