Extended Features i.e. Lane Assist, Junction View and Speed Limit work with City Navigator Maps.
To check if your device supports these functions do this
Press Battery Icon for +- 10 seconds
Press Next
Press Start Test
Press More
In the inventory screen you should see a line like the line below.
Splash D1340-50 2.00 nuvi narrow+wide,TTS,TRF,LA,J Pass
If you get this line your flash was successful. If it differs the flash was not successful.
Download a Small City Navigator unlocked img and corresponding JCV file to test in simulator mode.