I have just went from an upgrade from 11.04 to 12.04 LTS.
While I cannot find an "expected" listing of /etc/grub.d/
for different OS versions anywhere, from another computer I have access to, the original 11.04 entries are:
$ ls /etc/grub.d/
00_header 10_linux 20_memtest86+ 40_custom README
05_debian_theme 20_linux_xen 30_os-prober 41_custom
On the updated PC, after the update, I have:
$ ls /etc/grub.d/
00_header 10_os-prober 30_memtest86+ 40_custom
05_debian_theme 20_linux 30_os-prober 41_custom
10_linux 20_linux_xen 30_uefi-firmware README
Obviously, I've gotten some entries there which are duplicates - so not even running sudo update-grub2
as @Samik suggest does not remove duplicate entries in this case.
The answer for this case would obviously be to remove the duplicate _os-prober
and _linux
entries, and then running sudo update-grub2
.