Got a TomTom ONE with the following configuration:

Prog 8.412 OS:303268
map: Scandinavia_855_2883

I've tried to install different scandinavian maps like scandinavia 895.4444 that supports my navcore version 8.412. but I always get this map is not supported by your device after I have run the installer. What am I missing here?

I'm missing the necessary details...
Procedure is the the same like your last update.
Have you tried the current map version and the correct version of FastActivate? I assume not... ;)

I've been downloading and using the automatic installer, don't this have everything included?

k, figured it out - thnx :)

Thanx for the update.

Current map for your device is Scandinavia 900.4608!!