Loading and validating bios binary file
You also cannot configure the boot process from outside of the firmware. Now let’s look at how booting works on a UEFI system.Even if you don’t grasp the details of this post, grasp this: .
All a BIOS firmware knows, in the context of booting the system, is what disks the system contains.
UEFI is meant to be more generic, and can be found on systems which are not in the ‘IBM PC compatible’ class. Its predecessor and basis, EFI, was developed and published by Intel. It is a broad consensus specification, with all the messiness that entails, some of which we’ll talk about specifically later. If you really want to understand UEFI, it’s a really good idea to go and read the UEFI specification. One is the world of IBM PC compatible computers – hereafter referred to just as PCs – before UEFI and GPT (we’ll come to GPT) existed.
This is the world a lot of you are probably familiar with and may understand quite well.
You cannot make a little tweak to a system designed for the world of BIOS booting and apply it to . They are talking about using a UEFI firmware’s ability to boot the system ‘BIOS-style’ rather than native UEFI style. If you have a UEFI-based system whose firmware has the BIOS compatibility feature, and you decide to use it, and you apply this decision consistently, then as far as booting is concerned, you can pretend your system is BIOS-based, and just do everything the way you did with BIOS-style booting.
Many UEFI firmwares can boot a system just like a BIOS firmware would – they can look for an MBR on a disk, and execute the boot loader from that MBR, and leave everything subsequently up to that bootloader. If you’re going to do this, though, just make sure you not on the same disk.