If you are a bit confortable with xterm, use
dpkg --get-selections and export the list of installed applications
then do set-selections on the new firmware, copy back your old sources.list and everything is reinstalled.
That's what I need for the last upgrade. It's the usual debian way, should be easy to find from google or probably on this forum.

Actually, I think this mechanism should be part of the GUI because asking people to go in xterm is never a solution for everybody.