[syslinux] Option to create livecd using new syslinux to support multiple machines.

[Klaus Knopper]

Hello Michael,

On Fri, Jul 05, 2013 at 07:15:32PM +1000, Michael D. Setzer II wrote:
> Wondering what the best process would be to create livecds using 
> the newer version of syslinux.

For BIOS mode, I currently stay with the "old" syslinux 4 version for
now, if you don't need any of the new features or modules.  Version 4
was monolithic and rock-stable, and BIOS loading has not changed much
since the early days.

> Currently my G4L project has just been upgraded to syslinux 5.10 
> and works fine with regular 32 and 64 bit systems using the 32bit 
> kernels, but have seen comments about EFI and somethings 
> about 32bit only working with 32bit and 64bit with 64bit?

EFI looks for a 64bit loader /efi/boot/bootx64.efi by default on 64bit
machines, and looks for a 32bit loader /efi/boot/bootx32.efi by default
on 32bit machines. Both can be renamed from the right bitness version of
syslinux.efi (plus ldlinux.e32 and ldlinux.e64).

My own experiments showed that the current GIT version of syslinux.efi
will only start the kernel with a matching bitness, otherwise it crashes
and in the best case, brings you back to the EFI menu. I.e., you will
need a 64bit kernel and 64bit syslinux.efi for starting a 64bit
EFI-booting computer, and a 32bit kernel, 32bit syslinux.efi for a 32bit
EFI-booting computer (do they exist?).

Booting a 32bit kernel on a 64bit computer is, as far as I can tell,
currently not possible with syslinux.efi. You will have to switch the
computer to the CSM (BIOS compatibility) mode in order to use the BIOS
version of syslinux there.

> Since I average about 1,000 downloads per week, I would expect 
> that a range of computers are being used, so looking if a single 
> setup will continue to work, or if multiple builds will be required?

I use syslinux 4 for booting in BIOS mode, and syslinux.efi 32- and
64bit from the "firmware" git branch with two different kernels in the
Knoppix 7.2.0DVD, installed on USB flash disk version. You may want to
have a look at the directory structure there. The
/boot/syslinux/syslinux.cfg file can be reused for both, but
syslinux.efi currently can't load lss16 boot splash graphics, so the
boot picture is missing in EFI mode.

Regards
-Klaus