Comment 95 for bug 477169

I see two problems evident from some of your grub.cfg files, if in fact you're attempting to make use of a separate /boot filesystem as I recommended:

1) The "loopback" line should be referencing "boot.disk", *not* "root.disk". I'm pretty sure that grub is doing this in /usr/lib/grub/grub-mkconfig_lib, so that script will probably require a patch as well in order for update-grub to work right.

2) Your "linux" and "initrd" lines should *not* start with "/boot". They should simply be referencing "/vmlinuz..." and "/initrd..." without any "/boot" at the beginning of the path. Reason being is that these files now exist at the root-level of the boot.disk filesystem, as grub sees them. When I run update-grub, my grub.cfg file looks correct, there's no "/boot" at the beginning of these paths. So I can only guess that you're not running update-grub while your new /boot is mounted, which you have to do.

If you make these changes manually to your grub.cfg, you should be able to boot as normal from the menu, at least with kernel -14. I haven't yet had time to test the new -15 kernel update, so I can't comment on those problems.