Is linux kernel boot parameter root=live:LABEL=$iso a valid option for Ubuntu Live booting, e.g. Lubuntu 20.04 LTS?
I was making various GNU GRUB 2.04 menu entries to boot into a live session of Lubuntu 20.04 LTS, and it works fine. In my research I found a reference to setting the root of the GNU/Linux environment, but I'm unsure if it would apply to /casper live session booting. I suspect not. I've been using the GNU GRUB loopback loop parameter to do this for 12 years now.
See here: https://man7.org/linux/man-pages/man7/dracut.cmdline.7.html
menuentry "Lubuntu 20.04.3 live no persistence" {
search -n -l T7 -s
set isolabel="Lubuntu 20.04.3"
set isofile=/lubuntu-20.04.3-desktop-amd64.iso
loopback loop $isofile
linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=$isofile root=live:LABEL=$isolabel ro rd.live.image noeject noprompt
initrd (loop)/casper/initrd
}
The above menu entry works just as well as the below:
menuentry "Lubuntu 20.04.3 live no persistence" {
search -n -l T7 -s
set isofile=/lubuntu-20.04.3-desktop-amd64.iso
loopback loop $isofile
linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=$isofile ro noeject noprompt
initrd (loop)/casper/initrd
}
Since the url I found this information is a man page for dracut, I suspect the kernel parameter only applies to initramfs images created with dracut.
If so, then the question becomes, was the initramfs found /casper of the above iso created with dracut? Perhaps the source code tree will reveal this.