Comment 3 for bug 1817050

This feels to me like a missing piece in the current image build behavior. When preparing the classic image, we delegated the assembly of all grub (bootloader) bits to the gadget tree. Because of that, we were discarding the /boot/grub/* files from the root filesystem to not duplicate the boot info in both the rootfs build and the gadget build. But obviously we missed the fact that in case of grub, we need to have the bootloader configuration in both the boot partition and rootfs. Right now our gadget-prepared grub bits only go to the boot partition.

I obviously missed this part during the classic image preparation reviews since generally for model-assertion based builds ubuntu-image doesn't have to worry about this. For core images the /boot/grub directory is the mount point of the boot partition, so it's enough for everything to be in the gadget.

I think we'd want parity with what the core images do in this case, i.e. mounting the boot partition at /boot/grub. In my opinion this should make sense for preinstalled images, additionally allowing for upgrades of the boot partition contents (currently that's not possible). Would that be a senseful solution for preinstalled ubuntu classic images?