Comment 22 for bug 345542

You can look through the Ubuntu changelog and see if any Ubuntu changes were made, then (since the -4 is based on 2.6.28 and the -5 on 2.6.28.1) check the upstream changelog between 2.6.28 and 2.6.28.1.

If someone can build a vanilla 2.6.28 and 2.6.28.1 and test and compare, to rule out any Ubuntu changes, it would be great.