The boot loader can be manipulated at startup by holding down various key combinations to alter the booting process.
To make the boot loader appealing to other operating system developers, Apple added features to allow flexibility in the booting process such as network boot using TFTP and load Mach-O and ELF formatted kernels.
system as Grub (the boot loader) will not recognize the LVM boot partition.
What about the boot loader, which might have been altered to read a boot block from a non-standard location on the disk?
When the Load button was pressed the card reader would read in the first card, the I-Addr register was set to 001 so execution began in address 001 and so the boot loader would begin (let me know if you want a more indepth explanation about the boot loader).
The EFI partition is where the boot loader is installed and tells your PC which operating systems can be booted.
Security researcher Will Strafach told TechCrunch that the code is compelling for the information it gives hackers into the inner workings of the boot loader.
"Apple does not use security through obscurity, so this does not contain anything risky, just an easier to read format for the boot loader code.
Point the boot loader at the new kernel so it can be started.
What you see here is the first sector (sector 0) of your hard drive which contains the boot loader code, the master boot record and the partition table.
