3DR online instructions for online maps (same as posted here) is not valid for Tower 4.0. Mapbox is no longer listed as a map provider. The only choices are Google and Baido (from China?). If one follows the online instructions the map provider continues to show as Google. The instructions worked for Tower 3.2.1, but no more. The choice of Mapbox is no more on 4.0 Does anyone know how to enable offline maps for Tower 4.0?
I"m sure the Tower devs will respond once they see your post.
If not, you can use QGroundControl to cache offline maps. You can create sets of offline maps targetted to different areas specifying the zoom levels you want. QGC also supports MapBox. Doc here: https://donlakeflyer.gitbooks.io/qgroundcontrol-user-guide/content/SettingsView/OfflineMaps.html
