GRUB2 booting from LiveCD ISO files?

[Joe Boyle]

Hi there,

I've been experimenting with the livecd-creator tools on CentOS for
about a week now and made a lot of great headway for a project I'm
working on.

I'm hoping someone can help me with a problem I've bumped into - I am
struggling to create a GRUB2 entry which I can use to boot the LiveCD
ISO files I am creating with LiveCD.  (I understand I could use
livecd-iso-to-disk to copy the contents of the ISO to a partition,
which I may ultimately have to do, however, I am hoping to be able to
boot the ISO directly.)

I think I'm quite close, as the following entry will correctly locate
and start the ramdisk:

menuentry "test image" {
      set isofile="/iso/livecd-centos-livecd-minimal-201205310801.iso"
      loopback loop (hd0,3)$isofile
# everything below here is suspect and made with imagination sauce:
      linux (loop)/isolinux/vmlinuz0 setkmap=us isoloop=$isofile
      initrd (loop)/isolinux/initrd0.img
}

However, during device detection, I receive this:

WARNING: Cannot find root filesystem!

I recognize this isn't entirely a LiveCD creator issue, as it relates
to both GRUB2 and kernel boot options, but I am hoping someone has
covered some of this ground in the past and can suggest something
helpful.

I suspect I'm not using the right kernel options, and am not sure
which kernel options would be appropriate for the centos livecd.

Thanks for reading, any/all advice is appreciated,
Joe