@minay100
I think your problem hasn't been fully understood until now. Maybe you could give some more information as to what happens when you install a 3rd party map like the unrestricted "Roads of Belarus"? i.e. Does it not appear in the devices map info? Does the device show a message on start up ("Map cannot be unlocked" or "Map cannot be authenticated" for instance)? Also are you installing the map to the device memory or on microSD and also what path and naming?