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

JVC folder from .system deleted
mad MAP folder on SD card and insert CN NT 2014.20 EU and gmap3D.img
made JVC folder on sd card ( /Garmin/JVC )
Put in here the JVC files

Maybe they're just typos and you actually have 'JCV' naming not 'JVC'. If it's wrong fix that and try again. If you have it right as 'JCV', follow the rest of this:

Is the JCV file recognised in the units Inventory? To find it: Press and hold battery symbol until a hidden menu pops up>repeatedly press 'Back' or 'Next' until you see a page with 'Version Information etc' at the top>press Start Test>More. Under the Map listings just above 'Splash' you should see 'JCV' and it's details. Doesn't mean it's the correct file though, just means the unit's seeing it.

There is a similar solved discussion in the 1xxx upgrade thread, read from [Only registered and activated users can see links. ].

Are you also sure you have the correct JCV file for the detail map version. The files are different for each version. Remove any old JCV files too as they can interfere with proper operation of new JCV files.

Finally, did you clear NV before and after conversion? Did you scroll thru quite a long simulated route along a major highway? Nowhere near all 'junctions'/major exits have a Junction View pic.

Very common mistake (due to speed of typing and habit) : JVC (Japan Victor Company) instead of Garmin's JCV (JunCtion View)

It seems you're using the 'non-unicode' EU [Only registered and activated users can see links. ], i'd suggest a switch to the one that Garmin issues and recommends for all 3xxx series which is the Unicode map: [Only registered and activated users can see links. ]. You can get all the extra files for your 3490 which now uses different ASR files etc to when it was a 3790. The map coverage is the same for EU and EUU and the hi-res split-screen fiile D3048120A.JCV is available for it.

Re-reading i see that it's a 3760 that you've converted to 3490, not a 3790 as i thought. Even so you now have ASR but of course didn't have that as a 3760 so my comment about previously using different ASR files is irrelevant. As to your other queries:

Originally Posted by Chippie

..........
I have got this Garmin 3760 because the USB trough the active mount is not working. Charching no problem but it will not find the GTM35 traffic receiver.

Are you sure the problem is with the mount? Maybe the GTM35 is faulty. Do you mean the traffic symbol is 'greyed out' on the map screen or is it constantly searching for service? Sometimes the fm receiver fails in them but they do still charge. I have an old GTM25 like that and I've seen others. Try to borrow a traffic receiver, your unit's compatible with GTM 25, 26, 35 and 36 now as it was before, and now as a 3490 the HD Digital GTM60 should work too.

... Also USB to PC over the active mount is not working. Now I use the micro usb port.

All 3xxx units connected to pc via the mount with mini USB only charge and they run normally in navigation mode. That is correct behaviour. Only by connecting to pc via the unit's micro USB port will you access the PC via either Mass Storage or MTP modes [the latter being a setting in 3xxx 2012 & later devices].

Originally Posted by Chippie

Until now i haven't tried another one but I think you are right. The symbol is grey and also in the 'hidden menu' there is a string gtm25: not found or not detected

Thanks for your help :-)

Try cleaning the mount's usb port and the GTM35's plug with contact cleaner. Also use WebUpdater or GarminExpress to see if you are offered anything traffic related. Particularly updated GTMxx software because i vaguely recall there was a fix awhile back for greyed out icon and traffic lockout. If your current receiver still doesn't work after that but you manage to borrow another and find it works then your GTM's FM receiver is probably u/s.

Originally Posted by microjys

I have a 3490LMT us, I want convert 3790t(CHINESE) firmware to it .is it dangerous?

This thread is about converting 37xxUS to 34xxUS.
Converting 34xxUS to 37xxUS leeds to brick 34xx.
Open a new thread , here is OFF TOPIC