GRUB2 Live ISO Multiboot

http://github.com/thias/glim | http://glee.thias.es/GLIM

Overview

GLIM is a set of grub configuration files to turn a simple VFAT formatted USB memory stick with many GNU/Linux distribution ISO images into a neat device from which many different Live environments can be used.

Advantages over extracting files or using special Live USB creation tools :

• A single USB memory can hold all Live environments (the limit is its size)
• ISO images stay available to burn real CDs or DVDs

Disadvantages :

• There is no persistence overlay for distributions which normally support it
• Setting up isn't as easy as a simple cat from the ISO image to a block device

My experience has been that the safest filesystem to use is FAT32 (surprisingly!), though it will mean that ISO images greater than 4GB won't be supported. Other filesystems supported by GRUB2 also work, such as ext3/ext4 and even NTFS, but the boot of the distributions must also support it, which isn't the case for many with NTFS.

Screenshots

Installation

Setting up GRUB require you to be root, while the rest doesn't.

Set the USBMNT variable so that copy/pasting examples will work (replace /mnt and sdb with the appropriate values) :

export USBMNT=/mnt
export USBDEV=sdb

Preliminary steps (usually already completed on a newly purchased USB memory) :

• Create a single primary MSDOS partition on your USB memory.
• Format that partition as FAT32

Next, install GRUB2 to the USB device's MBR, and onto the new filesystem :

grub2-install --boot-directory=${USBMNT:-/mnt}/boot /dev/${USBDEV}

-or- (Ubuntu, for instance)

grub-install --boot-directory=${USBMNT:-/mnt}/boot /dev/${USBDEV}

If you get the following message :

source_dir doesn't exist. Please specify --target or --directory

Just find your grub2 directory and specify it as asked. Example :

grub2-install --directory=/usr/lib/grub/i386-pc --boot-directory=${USBMNT:-/mnt}/boot /dev/${USBDEV}

Use --force if your partitions start at 63 instead of more, such as 2048, though you might want to repartition and reformat.

Next, copy over all the required files (grub.cfg and files it includes, theme, font) :

rsync -avP grub2/ ${USBMNT:-/mnt}/boot/grub2

If you want to avoid keeping unused translations, themes, etc, use this instead :

rsync -avP --delete --exclude=i386-pc grub2/ ${USBMNT:-/mnt}/boot/grub2

Now create and populate the ${USBMNT}/boot/iso/ sub-directories you want. Example :

mkdir ${USBMNT:-/mnt}/boot/iso
mkdir ${USBMNT:-/mnt}/boot/iso/ubuntu

The supported sub-directories (in alphabetical order) are :

antix
arch
bodhi
debian
fedora
gparted
grml
ipxe
kali
knoppix
linuxmint
rhel
sysrescd
ubuntu
xubuntu

Any missing sub-directory will have the matching boot menu entry automatically disabled, so to skip any distribution, just don't create its directory.

Download the right ISO images to the newly created directory. If you require different versions, or just part of a distribution, edit the appropriate inc-*.cfg file.

Note that on 32bit computers, all 64bit entries will be automatically hidden.

Special Cases

Red Hat Enterprise Linux

RHEL isn't "live" as such. And in order for the install to work, you need to also copy the "images" directory from the DVD next to the DVD ISO, and keep only "install.img" and "product.img".

OpenELEC

OpenELEC isn't provided as ISO images, not is it able to find the KERNEL and SYSTEM files it needs anywhere else than at the root of a filesystem. But it's useful to enable booting the OpenELEC installer by just copying both files from any single version (ION, Intel, Fusion, Generic, etc.) to the root of the USB memory stick, instead of first having to create a new separate USB memory just to run the installer. As of OpenELEC 3.0, Live booting is also supported, but :

• The FAT filesystem's label must be 'GLIM'
• The first launch will create a 512MB file as /STORAGE This can be tweaked as needed by editing inc-openelec.cfg.

antiX

antiX kernel can't boot from an ISO image (it lacks options for iso file handling). The ISO file content must be extracted to the directory iso/antix/<ISO file name w/o extension>/ for GLIM to be able to launch it.

Note that antiX iso files contain a symlink, which is NOT supported by FAT file systems. Just skip it and it will work fine, but ensure that every other file is copied (the error caused by the symlink may stop extraction prematurely when extracting files directly to the USB memory stick).

Testing

With KVM it should "just work". The /dev/sdx device should be configured as an IDE or SATA disk (for some reason, as USB disk didn't work for me on Fedora 17), that way you can easily and quickly test changes. Make sure you unmount the disk from the host OS before you start the KVM virtual machine that uses it.

Troubleshooting

If you have any problem to boot, for instance stuck at the GRUB prompt before the menu, try running grub-install again. If you have other exotic GRUB errors, such as garbage text read instead of the configuration directives, try re-formatting your USB memory. I've seen weird things happen...

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Copyleft 2012-2013 Matthias Saou http://matthias.saou.eu/

All configuration files included are public domain. Do what you want with them. The invader logo was made by me, so unless the exact shape is covered by copyright somewhere, do what you want with it. The terminal_box_*.png files are CC-BY-SA-3.0 and come from the GRUB2 starfield theme by Daniel Tschudi. The ascii.pf2 font comes from GRUB, which is GPLv3+ licensed. For more details as well as the source code, see http://www.gnu.org/software/grub/