boot problem

[Ralf Mardorf]

PS:

"It is recommended to always use GPT for UEFI boot, as some UEFI
implementations do not support booting to the MBR while in UEFI mode." -
https://wiki.archlinux.org/title/partitioning#Choosing_between_GPT_and_MBR

IIUC without "Legacy" compatibility you also need to ensure that the
drive doesn't use MBR.

I still format all my drives using MBR. Maybe I should consider to stop
continuing with this, to avoid issues, if I need a new mobo. Perhaps
more companies will drop "Legacy" compatibility, too.

I just had a brief look at

https://serverfault.com/questions/963178/how-do-i-convert-my-linux-disk-from-mbr-to-gpt-with-uefi

Maybe it's possible to migrate from MBR to GPT without data loss. I
don't know. Whatever is claimed by the link, I would backup the
complete install first.

There seems to be information related to GRUB, too. That wouldn't help
me, since I'm using another bootloader, syslinux, but you are probably
in favour of GRUB.