Re: Chainloadig from grub2 to isolinux

[Raif S. Berent]

Not to beat a dead horse, but I'd like to clarify a few issues that
seem to be not working.

1. I compiled and installed Grub_trunk on an old laptop, then copied
the debian.iso to a folder under (hd0,gpt*). Modified the grub.cfg and
tried to use "syslinux_configfile -i (loop)/isolinux/isolinux.cfg -r
(loop)" I got the exact same result as PXE booting (No CD-ROM). From
what I can tell, debian needs the loopback module from the iso loaded
and the iso to be loop-mounted as a second device in order to get this
working (have not asked the debian folk).

2. Most Debian-based iso's fail to properly boot with loopback over
PXE, including the likes of GParted and Inquisitor. They mostly fail
with kernel panic: can't mount root.

3. MEMDISK: There were several programs I can boot from my USB setup by
including syslinux memdisk. These now fail due to memdisk error - for
example (<...> means options I have tried): menuentry "HDT: hardware
diagnostics tool" { set root="http,192.168.2.100" set
memfile="/pub/tftp/rescue/rscd/memdisk" set
isofile="/pub/tftp/rescue/rscd/hdt.img" linux16  ($root)$memfile
<keeppxe floppy raw safeint> initrd16 ($root)$isofile   }
With PXE, memdisk may need to be replaced with gpxelinux.0, but that
will require using Grub's broken pxechain. Is there a better way to do
this? syslinux apparently can also use memdisk for iso booting KERNEL
memdisk  \  APPEND iso initrd=http://192.168.2.100/path/isofile.iso

4. I think it would be a great idea if known grub.cfg entries could be
listed in the official Grub-wiki. The distro maintainers might also be
convinced or willing to post their code and solutions regarding iso
loopback from HDD/USB/PXE variations. I don't know, Just an idea...

Regards.