eTrex 30x comes with the "[Only registered and activated users can see links. ]"
Scale is 1:100.000 which I think is not detailed enough.

I haven't updated the firmware of the eTrex yet (still at v2.0) and all maps which can be downloaded on this forum work great.
A firmware update might disrupt this possibility.

I can't advise you on which map to use for Norway, but [Only registered and activated users can see links. ] looks like a good start.

Quality of OSM maps depends on the region: one region could be extremely good, other region could be inaccurate. Don't know the quality for the Norwegian part.