That is disappointing. I can't imagine the 3760 and 3750 are that much different. Just to be sure: what were you seeing on the myMaps settings screen? I see:
CN North America NT
and there is a checkmark on the left. This tells me it is unlocked, present and enabled. Again, I am sure you have a similar map for EU.
Note: the 3D building view also works even if you do not have the corresponding regular map. For example, I have the EU map installed and the North America 3D map: I can see the 3D buildings in the USA even if the US map is not installed.
I used Fast IMG Unlocker v 2.1 for CN Russia NT 2012.10 3D and i haven't seen buildings at all (2D or 3D). Any way i left my 3760 in the car and can't check right now. I'll check it tomorrow.
fw_all shows SW version 220
boot.bin shows SW version 430
have unlocked 3D file copied to .syste,
copied the file to .system, deleted the other one. Then did a hard reset after reboot. Nothing seems to have changed. Under System settings, still hows 4.30. I dont see anything changed.
Anything ive done wrong?
Try the chinesse FW.