Howto boot ISO images via grub2 with ubuntu


I am using Ubuntu “Daily builds” for some time inside Suns VirtualBox. Unfortunately the daily builds are not longer booting inside VirtualBox for more then 2 weeks now. Christian told me about a new feature of Grub2. You can boot ISO images directly from your hard disk without burning them on CD or USB. Awesome feature and I had to try it today. Here is the description on how to do it with Ubuntu 9.10.

First I am using this tiny script to update all daily builds with the zsync tool. It transfers only the changed parts of the ISO so you and the Ubuntu teams save a lot of traffic.

cd kubuntu
cd ../netbook
cd ../xubunutu
cd ..
rm `find ./ -name "*.zs-old" `

This script keeps all my daily builds up to date.

Next Step is to enable the grub menu. In Ubuntu it can be done in “/etc/default/grub“. Change the following lines


With this change you will see a 10 seconds count down when booting up. With the shift-key you get access to the grub boot menu. Next is to add the ISO images to the grub menu. Change to the “/etc/grub.d” dir.

Here you can find the grub menu entries and configuration files. Add your ISO images starting with 50 here. For example my entry for the normal Ubuntu ISO image (50_ubuntu) looks like this:

echo "Adding $(egrep menu[e]ntry $0 | cut -d'"' -f2)" >&2
 cat << EOF
menuentry "Ubuntu 10.04 Daily Build" {
       loopback loop (hd0,3)/ansi/software_and_config/ISOs/ubuntu/lucid-desktop-i386.iso
       linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=/ansi/software_and_config/ISOs/ubuntu/lucid-desktop-i386.iso file=(loop)/preseed/ubuntu.seed quiet splash bootkbd=sg --
       initrd (loop)/casper/initrd.lz

My ISO files are stored on sda3 under /ansi/software_and_config/ISOs/ubuntu/. In order to change it for your needs there are 3 elements to change. The loopback line contains your hard disk in grub style (hdx,y x=0->sda x=1->sdb aso) and the path. The third element to change is in the linux line. Store this file as “50_ubuntu” in “/etc/grub.d“, make it executable with “chmod a+x 50_ubuntu” and activate the changes with “ubdate-grub“. After a reboot you should be able to activate the grub menu with the shift-key and select the new entry. Have fun.

I found some pages on this topic but the description there was not working for me so I changed it. But take a look on your own:


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Reader's Comments »

  1. By dan on June 9, 2012 at 04:37

    nowhere is explained how to boot a non ubuntu image :/

  2. By ansi on June 11, 2012 at 10:34

    Hi Dan,
    thats right. I think its because of the daily build characteristic. But the mechanism must be the same for all ISO images.

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