Linux based booting and such

Because security

To be honest, even Apple's implementation of EFI is fairly different from the UEFI standard. Haswell and later Macs fully comply with the UEFI standard, but contain some additional stuff as well that isn't part of the UEFI specification.

And besides, Apple's implementation of BIOS is very basic. Read here for more: http://sealedabstract.com/rants/how-not-to-install-windows-on-your-macs-external-disk/

So this is why it's so hard to do what you want to do.

 

Perhaps things have changed, but the last time I used Ultimate Boot CD, it had a lot of programs that needed PC-BIOS compatibility. For example, when grub uses linux16 in the kernel definition, or syslinux uses memdisk to load a 16 bit FreeDOS image, that requires a PC-BIOS boot mode or some sort of BIOS emulation.

EFI (and UEFI) is for booting 32 bit and 64 bit operating systems, not for booting 16-bit MS-DOS and FreeDOS.

I suspect that the problems with the Ultimate Boot CD, have got little or nothing to do with linux, which uses a 32 or 16 bit kernel (even though some patches exist to port linux to 16 bit platforms).

I've been booting my linux desktop in UEFI for several years and the cMBP boots fine using GRUB-EFI.

One example here:
http://forums.macrumors.com/showthread.php?t=1844323

If you follow the instructions and use vmlinuz and core.gz from MicroCore linux 6.0 or later, the Mac should boot and the keyboard should be usable (at least on the cMBP). I've not had the chance to try this on a newer Mac

Of course if you want X-windows support for retina displays and other less common hardware, you might need the right parameters and the right drivers. But the same is true for porting Linux to any new hardware.


EDIT: I'm wondering if you were thinking that SYSLINUX is some part of Linux?

Just to be clear... SYSLINUX is a bootloader that was originally designed for booting Linux from floppy disks and later on used for other media that uses FAT file systems, such as USB flash drives. There is no requirement to use SYSLINUX or ISOLINUX to boot Linux and problems with SYSLINUX should not be considered to be anything to do with Linux compatibility.