Comment 10 for bug 413345

The same happens if the former jackalope-install used sda1 for grub and kernels and lvm /dev/mapper/ubuntu-jackalope for root.
it just assumes that all old systems boot from the new /dev/mapper/ubuntu-lucid even if it corrctly guesses the labels.

here are some lines from grub.cfg:
...
### BEGIN /etc/grub.d/30_os-prober ###
menuentry "Ubuntu, with Linux 2.6.32-16-generic (on /dev/mapper/ubuntu-jackalope)" {
        insmod ext2
        set root='(hd0,1)'
        search --no-floppy --fs-uuid --set 720da49e-1432-4601-9e1f-ac3335f1fa5e
        linux /vmlinuz-2.6.32-16-generic root=/dev/mapper/ubuntu-lynx ro quiet splash
        initrd /initrd.img-2.6.32-16-generic
}
...
menuentry "Ubuntu, with Linux 2.6.28-18-generic (on /dev/mapper/ubuntu-jackalope)" {
        insmod ext2
        set root='(hd0,1)'
        search --no-floppy --fs-uuid --set 720da49e-1432-4601-9e1f-ac3335f1fa5e
        linux /vmlinuz-2.6.28-18-generic root=/dev/mapper/ubuntu-lynx ro quiet splash
        initrd /initrd.img-2.6.28-18-generic
}
...