On 2022-06-13 20:06, Simon Becherer wrote:
Hi markus,
Am 13.06.22 um 19:06 schrieb Markus Koßmann:
On 13.06.22 15:54, Simon Becherer wrote:
i understand: in mbr there is a grub part somewhere in the first 2048 sectors who say -> load/boot/.... in gpt in the first 2048 sectors this is not the case.
Not exactly
When booting in legacy/CSM mode the BIOS loads the first 446 bytes from first sector of boot disk (= MBR, GPT provides a fake MBR) , checks if there is A5A5 magic number in the last bytes of MBR and then starts this as boot code. When grub is installed in MBR this code loads and starts the second stage of grub. Which is located on another position on the disk. With MBR partition scheme that code can be hidden in unused sectors of the disk. With GPT there are no unused sectors. So you will have to provide a BIOS boot partition for that code
"will have" -> must i? or is "/boot/grub2" also ok?
_Must_ It is a special dedicated raw partition, with dedicated type in GPT tables. At least GRUB MBR code can read it, using BIOS "interrupts". -- Cheers / Saludos, Carlos E. R. (from Elesar, using openSUSE Leap 15.3)