bea...@sdf.org (beaker) writes: >mlel...@serpens.de (Michael van Elst) wrote: >> Booting from a msdos partititon with a ffsv2 bootloader?
>It's not an msdos partion AFAIK but dkctl(8) lists it like that: That's because the partition type is marked as "EFI". > 269486080 125829120 3 GPT part - EFI System > Type: efi >Also AFAIK the primary bootstrap code is still installed on gpt3 (rdk2). Yes, but we learned that this bootstrap code will only handle GPT if started with a magic number in register %eax. Something that grub isn't doing. grub only passes the boot drive number in %edx and a pointer into the MBR partition table in %esi. So it's started with the same parameters as the MBR when called by BIOS (with the 16bit register counterparts DL and SI). If I understand the grub code correctly, the %esi pointer is 0 if the "parent partition map" is a GPT instead of a MBR. A compatible hack could check for this instead of the magic number.
