@atreio

If you convert 37xx to 34xx i think that you know how to downgrade FW.I cant know that you dont read post on this forum and search in Tutorial INDEX.
To downgrade your nuvi you only download FW 6.60 and rename it to gupdate.gcd and add in your nuvi in folder .System and restart nuvi.
I dont want to be rude,but please read and search in tutorial index ,you will learn a lot of useful thing about your nuvi.

p.s.
I read all your posts and i think other user too,but you only wait and wait in one Thread and you dont search and read other Threads where you can find all the answers.
Caty and other users create tutorials for help not because they have a spare time.
So please when you next time write something like you wrote in previous posts,i beg you to search around in the forum and you will see that all is already written and i always helped till today,but after that post i will go offline for some time,because you lift my preasure.

Lolly Over and Out!!!