GRUB2 Live ISO Multiboot

https://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
• ISO images are quick to manipulate (vs. hundreds+ files)

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, for instance. So FAT32 stays the safe bet.

Screenshots

Installation

Once you have your USB memory with a single partition formatted as FAT32 with the filesystem label 'GLIM', just run (as a normal user) :

./glim.sh

Once finished, you may change the filesystem label to anything you like.

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

almalinux
antix
arch
artix
bodhi
centos
clonezilla
debian
elementary
fedora
gentoo
gparted
grml
ipxe
kali
kubuntu
linuxmint
manjaro
memtest
netrunner
openbsd
peppermint
porteus
rhel
rockylinux
supergrub2disk
systemrescue
tails
ubuntu
void
xubuntu

Any unpopulated directory will have the matching boot menu entry automatically disabled, so to skip any distribution, just don't copy any files into it.

Download the right ISO image(s) to the matching directory. If you require boot parameter tweaks, edit the appropriate boot/grub2/inc-*.cfg file.

Items order in the menu

Menu items for a distro are ordered by modification time of the iso files starting from the most recent ones. If some iso files have the same mtime, their menu items are ordered alphabetically.

Here is a generic idea how to keep it nicely ordered when you have multiple releases of some distro:

• touch your release iso files with the release date
• touch your point release iso files with the original release date plus a day per point. This is a way to ensure point releases never pop above the next release like Debian 10.13.0 (released 10 Sep 2022) would still be below Debian 11.0.0 (released 14 August 2021)
• in case there are multiple flavours of some iso but the version is the same, touch all of them with the same date for the whole group to be ordered alphabetically

Sample ordered menu:

Special Cases

iPXE

The .iso files don't work when booting using EFI, you simply need to use .efi files instead.

LibreELEC

LibreELEC isn't provided as ISO images, nor 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 installer by just copying both files to the root of the USB memory stick. Live booting is also supported, and the first launch will create a 512MB file as /STORAGE.

Memtest86+

The .iso file doesn't work. Use either the .bin or the .efi depending on the boot mode used.

Ubuntu

Recent Ubuntu desktop iso images bundle multiple versions on the Nvidia driver. With that, the images are over 4GB, the FAT32 max file size. For example ubuntu-20.04.6-desktop-amd64.iso is 4.1GB, ubuntu-22.04.2-desktop-amd64.iso is 4.6GB. The driver is not required in a live system, it can be removed to make an image fit into 4GB. For example, with 22.04.2 image in the current dir:

mkdir slim
iso=ubuntu-22.04.2-desktop-amd64.iso

xorriso -indev "$iso" -outdev slim/"$iso" \
    -boot_image any replay -rm_r /pool/restricted/{l,n} --

Now you can copy slim/ubuntu-22.04.2-desktop-amd64.iso to your FAT32 formatted GLIM USB stick.

Some Ubuntu flavours also bundle the Nvidia driver (like Kubuntu), some don't (like Xubuntu). The same trick can be used with the former.

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. For UEFI testing, you'll need to use one of the /usr/share/edk2/ovmf/*.fd firmwares.

Troubleshooting

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

Contributing

If you find GLIM useful but the configuration of the OS you require is missing or simply outdated, please feel free to contribute! What you will need is to create a GitHub pull request which includes :

• All changes properly and fully tested.
• New entries added similarly to the existing ones :
  • In alphabetical order.
  • With all possible variants supported (i.e. not just the one spin you want).
• An original icon of high quality, and a shrunk 24x24 png version. Using convert -size 24x24 -background 'rgba(0,0,0,0)' original.svg small.png may work.
• An updated supported directories list in this README file.

Copyleft 2012-2023 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 background is "Wallpaper grey" © 2008 payalnic (DeviantArt) 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/