2 Brick after apply the patch for 3597 and others
Which patch for 3597?
I use a GarminCure/Updater for install a firm from scratch
Explain what have you flashed to your nuvi and how.
You must learn how to enter preboot mode to unbrick it with kunix's cure. Read with care how to and follow this post step by step [Only registered and activated users can see links. ]
So patience and retry because it's your only chance to unbrick it.
No NV backup? Bad move to play with firmware without it!