I know this is possible on the newer TomToms because I saw it on an ex-rental TomTom START 52.
What I want to ask is, how do you go about modifying the Startup Image?
Also, you can transfer custom POI files (ov2 format) to the newer TomToms using TomTom MyDrive Route Planner, but how do you delete them as there are no obvious options to do this in Route Planner?