[syslinux] Changes to get CD to boot on EFI System.

[Thomas Schmitt]

Hi,

Geert Stappers wrote:
> Don't tell it can't be done to those actually doing it

So you know how to boot from CD via EFI by SYSLINUX software ?
(Without putting a whole Linux into the boot image file, that is.)

Can you share the URL of such an ISO ?


Didier Spaier wrote:
> >> There is also goofiboot (fork of gummiboot) and even efi-stub

i wrote:
> > Do you know an example of them booting out of an ISO ?

Didier Spaier wrote:
> Yes, Solus ISOs.

That's the ones with the giant EFI boot image. We talked about them
in January ... says my mailbox.

The problem with such a boot image is that it might duplicate
functionality which is also present in the ISO filesystem for
the BIOS boot path via isolinux.bin.
E.g. in the EFI System partition of Solus-1.0.iso i see these files
in / :
  -rwxr-xr-x 1 root root 21206244 Dec 27 05:04 initrd
  -rwxr-xr-x 1 root root  5501728 Dec 27 05:04 kernel
and in the ISO in /boot :
  -r--r--r-- 1 root root 21206244 Dec 27 06:54 initrd.img
  -r--r--r-- 1 root root  5501728 Dec 27 06:54 kernel

(It would be a great stunt if the ISO files would indeed have their
 data content stored in the FAT image. But here they are duplicate.)


> PS as Ikey forked gummiboot, that he uses goofiboot is no wonder.

Do you think it is worth to ask him why the operating system has
to sit in the FAT image ?
(A Debian netinst ISO demonstrates how few data it needs to let
 GRUB2 hop out of the FAT and into the ISO.)


In my proposal a sentence ended wrong:
  "GRUB2 can hop out of the FAT filesystem on its own and make use
   of all files stored in there."
This should have been:
  "GRUB2 can hop out of the FAT filesystem on its own and make use 
   of all files stored in the ISO 9660 filesystem."


Have a nice day :)

Thomas