Bug#658352: amd64 UEFI support

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

i read on http://lists.debian.org/debian-devel/2012/01/msg00168.html

> 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.)


> 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.

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.


My knowledge about boot sectors in ISO 9660 images is collected in:
  http://bazaar.launchpad.net/~libburnia-team/libisofs/scdbackup/view/head:/doc/boot_sectors.txt
Prepared FAT partition content can be appended while Jigdo production. See
  http://www.gnu.org/software/xorriso/man_1_xorrisofs.html
for option -append_partition.


> An EFI System Partition is basically a regular partition, 

Recognized at boot time from MBR ? (Or from where else ?)


Have a nice day :)

Thomas