If you first search the forum or look in the [Only registered and activated users can see links. ] you will find some ideas.

[Only registered and activated users can see links. ]
[Only registered and activated users can see links. ]

The maps don't have the same complete MapID, just the same FID & PID data in some cases. The complete MapID is also with RgnID & VenID. Normally if RgnID = 0 & VenID = 0 when generating a key it unlocks all RgnIDs & VenIDs. cityXplorer maps uses PID = 2 for enhanced pedestrian mode data. The nüvi 775T can't use the enhanced pedestrian navigation mode and uses the cityXplorer maps like if it was just a City Navigator NT map.