[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Bug#658352: amd64 UEFI support

Thomas Schmitt, 2012-02-02 12:52+0100:
> > For optical media, I am not really sure: it may use ElTorito or load a
> > file /efi/boot/boot<arch>.efi from the ISO-9660 or UDF filesystem, so
> > this should be checked.
> GRUB2 grub-mkrescue can produce (U)EFI bootable ISO 9660 images, where
> booting shall start at the El Torito Boot Record. (I only provide the
> ISO image generator, so i have no insight what happens at boot time.)

All right, I was not sure of how optical media were supposed to be
handled since the UEFI specification is not very clear about them.
Regular El Torito then.

> > It would be possible to create hybrid BIOS/UEFI bootable images, but
> > that will probably be incompatible with hybrid USB/optical images as we
> > have them currently.
> Where would be the incompatibility with isohybrid ISOLINUX in particular ?
> If it is only lack of necessary UEFI support in SYSLINUX/ISOLINUX, then
> one could consider grub-mkrescue as base for optical media and USB sticks.

UEFI booting requires a GPT and a special partition, which would
probably be impossible to implement along with the MBR hack for hybrid

> It produces an MBR and El Torito boot equipment, which can point to
> boot loaders for PC-BIOS and to boot loaders for (U)EFI at the same time.
> It already uses xorriso as ISO generator. So Jigdo production would be
> no big problem.
> The MBR marks the ISO image and could mark a further FAT partition.
> I would also propose my pet feature, 32 kB offset of partition 1.

Well, perhaps that could work after all. But it would have to be a GPT,
not only an MBR.

> > An EFI System Partition is basically a regular partition, 
> Recognized at boot time from MBR ? (Or from where else ?)

Recognized by the UEFI boot manager, as a GPT partition with the correct

Tanguy Ortolo

Attachment: signature.asc
Description: Digital signature

Reply to: