I've tried using the below instructions but have a problem.

"Maps are unlocked but for enhanced pedestrian mode you need additionally *.unl file generated with Jetmouse Keygen
Use JetMouse Keygen to create an unlock code for your Unit ID and Custom Mapset with MapID --> 800. Write the unlock code to text file with name *.unl.
Save as "all files"
Copy files *.img, *_3D.img if present and *.unl to Map directory on your nuvi or preferably to SD card.
These unlocked maps will work in Nuvi 37xx series too ,abilitating pedestrian mode and public transports features-"

I downloaded City Explorer New York City.
I renamed the map gmapprom1 and copied to my Nuvi 1350T in System Folder
The map appears when reviewing installed maps.
The gmap3d.img was also copied to the system folder, this map does not appear.

I am not sure which map needs the unlock key, I assume it's the gmap3D.img.
Used the jetmouse KG with checksum and generated key for Map ID 800, named it gmap3d.unl put in System folder, but map does not appear.
Tried renaming the file gmapprom1.unl thinking the main map needs to be unlocked, that still doesn't let the 3D map appear.
This map must appear for the enhanced pedestrian feature to work, according to Garmin this feature works on the 1350T.

Can somebody please explain what I did wrong.