[syslinux] Is efiboot.img required?

[Curt Brune]

On Sun Apr 05 15:17, Thomas Schmitt via Syslinux wrote:
> None of the ISOs i know has this stuff in the FAT image.
> There must be some way for GRUB/GRUB2 to escape from FAT
> into the ISO.
> debian-7.7.0-amd64-netinst.iso does the job by a
> bootx64.efi binary of 421888 bytes. It's the only file
> in the FAT (of 458752 bytes).

[ long time syslinux user -- thanks all!! ]

At the risk of contributing to the 'urban legends' and the 'salads' I
have found this sequence of blog posts about UEFI/ISO/xorriso/GRUB2
enlightening:

http://lukeluo.blogspot.com/2013/06/grub-how-to-2-make-boot-able-iso-with.html
http://lukeluo.blogspot.com/2013/06/grub-how-to-5-ubuntu-distributition-iso.html

At the end of the described procedures is a single GRUB2 based .ISO
that can boot in 4 different ways (cross product of ISO9660/disk-image
and Legacy-BIOS/UEFI):

   $ qemu -m 512 -cdrom  ubuntu-13.04-desktop-amd64.iso
   $ qemu -m 512 -hda  ubuntu-13.04-desktop-amd64.iso 
   $ qemu -m 512 -bios OVMF.fd -hda  ubuntu-13.04-desktop-amd64.iso 
   $ qemu -m 512 -bios OVMF.fd -cdrom  ubuntu-13.04-desktop-amd64.iso 

Deepened my understanding greatly.  However, not for the casual user.

Cheers,
Curt