I obviously dont have a android dynavin, but I have an android phone. You can disable mobile network data, by going to settings> wireless> mobile network > disable mobile data.
There is also a mobile connection configuration section, I don't know if it exists in the Dynavin
Press *#*#4636#*#* to bring up Testing screen,
Go to Phone Information ,
Press menu button on the phone,
Tap on Disable data connection.
With the wireless data disabled hopefully it will force it to use Wifi.
///BMW 328CI 5 speed