If img FID is greater than 2200 Jetmouse is useless.
Use gimgunlock to unlock.
Backup old files (.unl&.gma) along old .img and remove them.
Copy unlocked .img to the same place of the previous one, no .unl or .gma is needed after running the unlocker on the .img.
Be sure to have a basemap in nuvi.
sent with my phone