[syslinux] Is efiboot.img required?

Thomas Schmitt
Sun, 05 Apr 2015 06:00:40 -0000

Hi,

piranna wrote:
> > Quoting http://www.syslinux.org/wiki/index.php/Isohybrid#UEFI:
> > "The additional isohybrid feature for UEFI adds a partition to
the MBR
> > partition table pointing to the same file in the ISO 9660 filesystem
> > as does the El Torito catalog entry for EFI."

Ady wrote:
> IMHO, the current content of the Isohybrid page in the Syslinux Wiki is
> not clear enough [...]  The current generic information is
> rather focused on _potential_ capabilities of _isohybrid_ tools and
> some of their internal technical characteristics, and less focused on
> actual practical steps for ends users.

Well, it is about really usable capabilities of isohybrid,
which regrettably only work with EFI boot software from
other bootloader projects.

isohybrid can mark a FAT filesystem image with EFI
boot software as EFI System Partition inside the ISO
image.  But SYSLINUX cannot provide a FAT image with
EFI boot software that works with an ISO 9660 filesystem.

All EFI isohybrid images known to me contain
/efi/boot/bootx64.efi from GRUB Legacy or GRUB2.


About fixing the wiki:

Would it be appropriate to mention the words "GRUB legacy"
and "GRUB2" in the SYSLINUX wiki ?

Would it be desirable to explain how Fedora et.al.
created their FAT boot images by help of old or new
GRUB ?
(If developers of EFI bootable ISOs are reading this,
 please give a short sketch of the procedure.)


piranna wrote:
> > (iso9660 can be seen as a read-only FAT filesystem)?

The meta-data structures of ISO 9660 are different from
FAT.