Thread: Transform a Nuvi 37xx in a Nuvi 34xx for dummies

Originally Posted by fringe

Do I need to convert it back to 3790 before making backup of NV or can I leave as 3490 and do back up?

You can make a backup without converting back to 3790. Best of all is to make backup with original 3790 before converting it to 3490, but now it's too late.

Thanks a lot. It worked for me. I still see flash screen as 3790. Is this normal?

Originally Posted by testle

Thanks a lot. It worked for me. I still see flash screen as 3790. Is this normal?

Yes Absolutely normal.

Followed directions to backup NVram. Modified txt file to include all regs (0-255). Successfully parsed reg 0-172 then errored for the rest.
Parsing "rrgn,172,1:/reg_172.bin"
Success
Parsing "rrgn,173,1:/reg_173.bin"
Error

Is this normal?

Originally Posted by fringe

Followed directions to backup NVram. Modified txt file to include all regs (0-255). Successfully parsed reg 0-172 then errored for the rest.
Parsing "rrgn,172,1:/reg_172.bin"
Success
Parsing "rrgn,173,1:/reg_173.bin"
Error

Is this normal?

Yes
Not all Regions are available.
Your commands are good.

For NVram backup you need to have a copy of region 41.
If you damage this region your Nuvi will go to 34xx (37xx) state.

For NVram backup you need to have a copy of region 41.

Backup of reg 41 was successful. Taken from 'converted' 3790.
Does the conversion 3790->3490 cause a change to reg 41 content?

Originally Posted by fringe

Backup of reg 41 was successful. Taken from 'converted' 3790.
Does the conversion 3790->3490 cause a change to reg 41 content?

Reg41 from 3790 vs 3490 is not the same. ( byte by byte comparing.)

Does converting back (3490 ->3790) restore the 3790 reg 41.bin to original
Trying to decide if it is worthwhile temporarily restoring my unit back to 3790 so as to backup original reg 41.

NV is changing all the time. What is important inside is model number, ID, registration code and unlock codes, you can see all in GarminDevice.xml. This doesn't change when flashing 3790 <-> 3490.