As to your question of sequence, I just got done upgrading my 2032's (CCWR) with the same 5.1 firmware as you. To upgrade to the latest, you need to go sequentially: 5.2.0 first, then 5.3.0, then 5.4.0, then 5.4.5.
Note, this is only for the WR models. Follow @alastairstevenson 's post for...