Le sam. 7 sept. 2024, 00:51, Pascal Hambourg <pas...@plouf.fr.eu.org> a écrit :
> On 06/09/2024 at 15:15, Askar Safin wrote: > > > > While testing this script I noticed this: if I boot from disk (i. e. > > using "-drive" Qemu option), then "grub.cfg" is read from ESP, i. e. > > FAT. But if I boot from CD (i. e. using "-cdrom" Qemu option), then > > "grub.cfg" is read from main .iso partition, i. e. iso9660. I don't know > > whether this is expected behavior or just a bug. > It's intended. ESP in El Torito is just an artifact of the spec. We always use entire iso9660 to store our files on all the platforms > > I do not know either, but it matches my previous observation. When > booting from a EFI partition on a regular disk, then $root is set to the > EFI partition (hdX,Y). When booting from a EFI El Torito image on a CD, > then $root is set to the whole CD (cdX), and the El Torito image is not > visible. > > > FAT is case insensitive from GRUB point of view. But iso9660 is case > > sensitive. So, the file (in case of CD boot) must be named exactly > > /EFI/debian/grub.cfg. Name /efi/debian/grub.cfg will not work, > I faced a similar issue when trying to use $cmdpath instead of the > hardcoded prefix /EFI/debian; the case in $cmdpath is variable and > depends on the UEFI firmware and boot method (from EFI boot entry, > select boot device, select EFI file). I have seen "/EFI/BOOT" most often > but also "/EFI/Boot" and "/efi/boot". > > On 06/09/2024 at 20:09, Thomas Schmitt wrote: > > > > I can confirm that many distro ISOs have a copy of the file tree of their > > EFI system partition as file tree "/EFI/boot" in the ISO 9660 filesystem. > > Nobody seems to complain about the mixed case. > > This copy normally plays no role in booting > > It plays a role in Debian ISOhybrid images when booting from CD with a > monolithic signed GRUB image which fetches an early grub.cfg in the EFI > partition, because GRUB does not see the El Torito image and can read > the early grub.cfg only from the ISO 9660 filesystem. > > _______________________________________________ > Grub-devel mailing list > Grub-devel@gnu.org > https://lists.gnu.org/mailman/listinfo/grub-devel >
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