On 2025-03-16, Michael <confabul...@kintzios.com> wrote: > Ugh! I didn't provide a comprehensive answer - sorry. All this MBR > nostalgia > I've been trying to forget. LOL! > > If you are installing GRUB on a GPT disk, which is meant to boot on > a legacy BIOS MoBo, you *must* create a BIOS Boot Partition (gdisk > code EF02). GRUB will drop its boot.img in the disk's MBR (sector > 0) then would try to install its core.img in sector 1, exactly where > GPT has stored its own primary table. With a BIOS Boot Partition > this clash is averted.
You /can/ use an embedded block list to install legacy BIOS boot mode grub using an MBR table without a BIOS Boot Partition, but don't do it. It requires manual intervention any time grub gets updated, so it's a pain to maintain. The "right" answer is to create a BIOS boot partition. Then it will "just work".
