Bug#922251: live-build: support syslinux-efi as (additional) bootloader
Hi,
Matthijs Kooijman wrote:
> > > https://www.syslinux.org/wiki/index.php?title=Isohybrid#UEFI
I wrote:
> > This describes the equipment of debian-live and debian-cd [...]
> I'm a bit confused by your message. When you say "This", are you
> referring to the syslinux isohybrid page?
Yes. The doings of SYSLINUX program "isohybrid" are also implemented in
libisofs underneath xorriso.
It was me who wrote that wiki page with info collected from the
mailing list syslinux@zytor.com and with my knowledge as developer of
libisofs and xorriso.
But currently i get "Connection refused" when trying to connect to
www.syslinux.org. So i can only see the Google "cached" document or
a text draft of mine from june 2014.
> > SYSLINUX EFI stuff is known not to boot from CD, DVD, or BD, but only from
> > HDD, SSD, and alike.
> Again, I'm confused. If syslinux-efi is known not to boot from
> CD/DVD/BD, then why do they document how to include it into an isohybrid
> image?
A little discussion on the list resulted in the decision not to mention
the SYSLINUX EFI problems or GRUB2. Courtesy among upstreams ...
Regrettably there is still no official position towards the failure with
SYSLINUX EFI code booting via El Torito from optical media.
But already the inventor of the "isohybrid" program's --uefi option,
Matthew J. Garrett equipped his Fedora ISOs by EFI software from GRUB2
together with BIOS software from SYSLINUX. (Plus some HFS+ filesystem
image pointed to by an Apple Partition Map.)
Maybe Steve McIntyre can contribute an anecdote how he came to the
decision in debian-cd to use GRUB2 for EFI and thus to create the need
for two independent boot menu configurations.
Klaus Knopper, on the other hand, believes that it could work on some
machines. But he tested only with virtual machines and i found no
confirmation that it works on any real iron in native EFI mode from DVD.
See e.g. this 4 GB image:
http://ftp.uni-kl.de/pub/linux/knoppix-dvd/KNOPPIX_V8.2-2018-05-10-EN.iso
> Or does it then only work when booting the isohybrid image from a
> HDD, rather than CD?
If you find a real machine that boots in native EFI mode Knoppix 8 from DVD,
then this would be a novelty. (Virtual machine firmware is known to be
sloppy with the distinction of HDD and CD-ROM boot paths.)
Have a nice day :)
Thomas
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