What is UEFI and how it is useful for Hackintosh
There are two basic methods of installing a bootloader: BIOS and UEFI. This article will explain them both, as well as what they mean for in terms of hackintoshing.
1 What is BIOS?
BIOS was the original firmware standard used on IBM PC’s and then by all the IBM clones. As such, it became the standard used by DOS and then Windows. It can be accessed by holding down a function key at boot and can edit basic hardware settings.
2 The BIOS Boot Process
The BIOS selects the drive to boot from and triggers the code in the MBR or Master Boot Record. This is the very first thing on the drive. The MBR then loads the bootloader which allows you to select a partition and trigger the kernel on that partition.
The kernel then loads the rest of the operating system.
The important thing of note here is that the BIOS can only see physical drives, not partitions.
What this ends up meaning is that BIOS is very simple. You install a bootloader to the MBR and that bootloader gets triggered. It is very good for dual booting between separate drives, as you can keep the bootloaders on each drive completely separate and distinct regardless of whatever partitioning you may have done.