Sorry, a complete offline navigation with NUNAV is not possible.
In the future it is planned that our users will be able to download a map section and thus the map can be loaded in WLAN and does not have to be loaded with mobile data while driving. This topic is currently under development. We therefore ask for a little more patience.
However, complete offline use will not be possible, as this would be contrary to our approach of networked driving. You can find more information about "Collaborative Routing" here.