Grub2 and multiple boot different ubuntu versions

[Tom H]

>>> In Collin's case, where he wants Karmic to be the default chosen, cut the
>>> whole bunch of karmic's entries and paste it *above* the lucid's entries.
>>> First entry below the .d10

>> If the Lucid entries are generated by 10_linux and the Karmic entries
>> are generated by 30_os-prober, for grub to display the Karmic entries
>> before the Lucid ones, all that you have to do is
>> mv 30_os-prober 09_os-prober
>> No need to edit
>> /boot/grub/grub.cfg

> That's a nice trick, will it stick? That is, will update-grub and kernel
> changes revert to original sequence?

Updates to grub2 have yet to modify (or delete) any file other than
00_..., 05_..., 10_..., 20_..., and 30_... in /etc/grub.d; even "chmod
-x..." is respected.