NOTE: This guide primarily applies to the UEFI on older Gigabyte motherboards with the LGA 1155 socket-- this means P67, Z68, Z77, H67, H77, B75, and Q77 motherboards. If you use a newer motherboard with the LGA 1150 socket, ignore the sections on xHCI and EHCI.
Essentially, the BIOS (or UEFI) is the settings page for your computer's motherboard. From here, you can fiddle with how your computer hardware works-- it's often necessary to change a few basic settings in the BIOS or UEFI to get Mac OS X up and running. The BIOS standard is generally used by motherboards from before 2012, while the UEFI standard is used by motherboards made after that.
|UEFI on the left, BIOS on the right|
To enter the UEFI on a Gigabyte motherboard, press the delete key when your computer boots (before the operating system starts). Different manufacturers set different keys for opening the UEFI. On some Gigabyte motherboards, this will bring you to the "3D BIOS". From here, you can choose which specific part of your motherboard that you want to manage.
Boot Option Priorities - Change "Boot Option #1" to your USB drive. You need to do this for Unibeast to work. After you finish installing Mac OS X, you should change this setting back to default, so your main hard disk is the first boot option (this optional, but it will speed up your boot times later on).
On Gigabyte motherboards, the settings page will often show you two versions of each hard disk: the UEFI version (usually labeled as "UEFI"), and the legacy version (usually labeled as "P", "SATA," or "Legacy"). If you installed OS X El Capitan through the Unibeast method, you must set the UEFI version as first priority. This is because Hackintoshes with El Capitan use the Clover bootloader, which only works with UEFI boot.
However, if you are installing an older version of OS X through the Unibeast method (e.g. Yosemite, Mavericks, etc.), you must select the legacy version as first priority. This is because Hackintoshes with older versions of OS X usually use Chameleon or Chimera bootloader, which does not support UEFI boot.