Boot LiveCD iso from grub2

[phenest]

I found an article regarding the loopback feature of Grub2 where by you could boot from an iso. Does anyone know if it's possible, if so how, to do this with the Ubuntu Live CD?

[blueridgedog]

The article you linked to and the one it links to ( http://michael-prokop.at/blog/2009/0...iso-via-grub2/ ) have pretty clear instructions. What part of the process is not working for you?

I would start by putting your iso in a known (such as boot) location and altering the line from the example from isofrom=/dev/sda1/grml/grml-small_2008.11.iso to isofrom=/dev/sda1/boot/myjaunty.iso (or whatever you called it).

[phenest]

Something like this:

menuentry "Ubuntu Jaunty Live CD" {
loopback loop (hd0,3)/steve/archive/iso/linux/karmic-desktop-amd64.iso
linux (loop)/casper/vmlinuz isofrom=/dev/sda3/steve/archive/iso/linux/karmic-desktop-amd64.iso root=/dev/sda3 boot=casper quiet splash noprompt
initrd (loop)/casper/initrd.lz
}

...just drops to a busy box.

[blueridgedog]

Something like this:

menuentry "Ubuntu Jaunty Live CD" {
loopback loop (hd0,3)/steve/archive/iso/linux/karmic-desktop-amd64.iso
linux (loop)/casper/vmlinuz isofrom=/dev/sda3/steve/archive/iso/linux/karmic-desktop-amd64.iso root=/dev/sda3 boot=casper quiet splash noprompt
initrd (loop)/casper/initrd.lz
}

...just drops to a busy box.

Did you verify the /casper/initrd.lz path and name on the image you are using? It is /casper/initrg.gz on mine. Also, try it without the root directive. How did you arrive at boot=casper? Did you try live?

[phenest]

On Karmic, it's initrd.lz, whereas it's initrd.gz on Jaunty. I've tried both Jaunty and Karmic with varying different options with no success.

boot=casper was taken from the boot options for Ubuntu.

[phenest]

The best I get is a BusyBox prompt.

[blueridgedog]

Try the commands one at a time at a grub prompt. You may get some more debugging information. I will mock it up on my end as well. Is the partition with the image a primary one (I assume it is as the first partition in an extended one would be hd0,5 in grub speak)?

[Herman]

menuentry "Ubuntu Jaunty Live CD" {
loopback loop (hd0,3)/steve/archive/iso/linux/karmic-desktop-amd64.iso
linux (loop)/casper/vmlinuz isofrom=/dev/sda3/steve/archive/iso/linux/karmic-desktop-amd64.iso root=/dev/sda3 boot=casper quiet splash noprompt
initrd (loop)/casper/initrd.lz
}

Try replacing 'initrd.lz' with 'initrd.gz' and see if that helps.
Regards, Herman

[phenest]

menuentry "Ubuntu Jaunty Live CD" {
loopback loop (hd0,3)/steve/archive/iso/linux/karmic-desktop-amd64.iso
linux (loop)/casper/vmlinuz isofrom=/dev/sda3/steve/archive/iso/linux/karmic-desktop-amd64.iso root=/dev/sda3 boot=casper quiet splash noprompt
initrd (loop)/casper/initrd.lz
}

Try replacing 'initrd.lz' with 'initrd.gz' and see if that helps.
Regards, Herman

POn Karmic alpha 3, it's 'initrd.lz'.

[kewarken]

I suspect none of this will work. To me, it looks like the 'isofrom' option is specific to the grml distro he's using unless it's also a ubuntu option. That is to say, unless there is some specific support in the init script for dealing with an iso, it's not going to happen.

Normal sequence:
- boot kernel and initrd
- mount some stuff like squashfs partitions or whatever from install media
- run init

Fancy grub2 sequence:
- boot kernel and initrd
- mount install media (using isofrom)
- loopback mount iso file from install media (using isofrom)
- NOW do the squashfs mounting, etc.
- run init

If you look at the isofrom option, it's giving both a device and a path to the iso so that steps 2 and 3 can happen. If distros are going to support this, it would definitely be handy for everyone to standardize on something like 'isofrom' to be sure.

cheers,

Kris