I just created a usb drive containing different linux distributions. I wanted the drive to have the original iso files on it with no need to unpack.
Here is what I did:
sudo mkfs.vfat -n MultibootUSB /dev/sdd1
sudo mount /dev/sdd /mnt/
sudo grub-install --no-floppy --root-directory=/mnt /dev/sdd
All iso files have to put to ‘/mnt/iso’.
My config file ‘/mnt/boot/grub.cfg’ can be downloaded here.
Especially the configuration for Arch Linux was a bit tricky to create.
‘archisolabel’ has to be the label of the image file used.
‘img_dev’ is set to the uuid of the usb device used.
Quite interesting is also the remastering of certain files. I put the neo keymap into /arch/any/usr-share.fs.sfs.
See here: https://wiki.archlinux.org/index.php/Remastering_the_Install_ISO. If anybody wants to have the iso file, just tell me.
For further information check:
http://www.panticz.de/MultiBootUSB
https://wiki.archlinux.de/title/Multiboot_USB_Stick
https://wiki.archlinux.org/index.php/Grub2#Booting_an_ISO_Directly_From_GRUB2
https://bbs.archlinux.org/viewtopic.php?pid=749337
https://bbs.archlinux.org/viewtopic.php?id=78171&p=3