Hi andrei, Am 13.06.22 um 09:33 schrieb Andrei Borzenkov:
On 13.06.2022 10:09, Simon Becherer wrote:
1) what would be the best way to change mbr to gpt -> maybe using gdisk?
Yes, this will work.
Are you sure your BIOS is capable of booting off NVMe in legacy BIOS mode? This would be rather unusual. well i changed in ueffibios: "csm" to on and control of boot drives: "only legacy"
and it did a boot also from the nvme
GPT/MBR just change partition table, legacy BIOS boots by loading the very first sector and jumping into it. Some BIOS implementations are known to verify that there is bootable MBR partition, in this case you would need to mark protective MBR partition as bootable.
the mbr partition-table was made with opensuse, and i have a directory /boot/grub2 so i did not know how it works in detail. there are only two/three partition ext4 on the drives, "/" and "/home", and on one drive a "linux swap" first partition starts at sector 2048
2) i found in /etc/default/grub_installdevice one line: generic_mbr i guess that this info has to be changed, what must be insert here instead of "generic_mbr"
This still works with GPT, in this case YaST writes Syslinux GPTMBR. You will also need to mark suitable GPT partition as bootable.
i do not understand my mbr ext 4 partition is bootable, so if i change to gpt i will loose this ?
If you want to install grub in GPT MBR, you will need BIOS boot partition. It better be located in the beginning to avoid any possible issues with BIOS access disk size limits.
here i do also not understand. actually i was thinking somewhere in mbr or gpt (the firts 2048 sectors) is the grub part which only says: "read /boot...." but maybe i am wrong, if i think for this, somewhere must be written that it must be read in ext4 style. maybe grub is able to read a lot of different haddrive filesystems. am confused. simoN -- www.becherer.de