[syslinux] Creating LiveCD with EFI option?

[Klaus Knopper]

Hello,

On Thu, Jul 03, 2014 at 10:58:11PM +1000, Michael D. Setzer II wrote:
> I've been using various versions of syslinux as the boot loader for the g4l 
> project that I have been the maintainer of since 2004. It was already using 
> syslinux, so I've just updated it over the years, and currently have it use 5.10 
> version, but have done test builds with the 6.x versions.
> 
> Recently had request from to users about EFI support, and one suggested 
> that virtualbox has option for testing, so I cloned the current testing of the 
> ISO to and EFI format, but just get a shell, so it requires some more steps. 
> 
> Did some searching, but haven't found anything that seems to have the exact 
> steps. Also, not sure if I could make a single iso that would work with both, or 
> have to create two different versions. In testing 6.x of syslinux, I just copied 
> the files  to a different directory and replace the 5.x versions with 6.x 
> versions, and build process remained the same.

You may check the current version of Knoppix 7.3 (or 7.2), which
contains a efi/boot directory with a patched version of syslinux.efi
that will read the standard syslinux.cfg file for 32bit, and
syslnx64.cfg for 64bit. This version, when copied to USB flash disk, is
know to work in both cases, the standard BIOS (called CSM in EFI) or EFI
mode, just no secure boot possible since the boot loader is not signed.

Seems to work on many notebooks set to EFI-boot, just apple seems to
have problems reinitializing the graphics card after having booted via
syslinux-efi (system invisibly boots to the desktop, but screen stays
blank, no graphics).

For testing in a virtual environment, I use

kvm -m 2000 -monitor stdio -soundhw es1370 -L Ovmf/ -hda sda.img -fda fd0.img

where directory Ovmf contains the open source EFI firmware from
http://sourceforge.net/apps/mediawiki/tianocore/index.php?title=OVMF

I did not test efi boot from CD yet, the above scenario is just for USB
flash disks with a primary FAT32 partition, as expected by the EFI
firmware.

Regards
-Klaus