Comment 28 for bug 963106

Daniel, try:

$ sudo update-rc.d -f umountroot remove
$ sudo update-rc.d umountroot start 60 0 6 .

Note the period at the end of the 2nd command. And yes, my previous
suggestion of using mv won't work, you have to use update-rc.d, sorry.

When I used update-rc.d to put umountroot at 03 as you have, I see the
same symptoms you do. Using the above commands to put it back to 60
fixes the problem. Hope this helps, please let us know.