Comment 9 for bug 1948895

I have some branches ready that should solve this problem + the grub.cfg upgrade scenario that Ethan mentioned (thanks for catching it!). It's still in review phase, I'll be creating some test images and if everything looks good, we can think of fast-tracking it somehow.

Basically these two changes need to land:
https://code.launchpad.net/~ubuntu-core-dev/livecd-rootfs/+git/livecd-rootfs/+merge/410949
https://github.com/snapcore/pc-amd64-gadget/pull/54