On my conputer I do not see the SD card or my Tomtom drive letter when I connect my Tomtom with USB port wiiht my laptop.

Windows 8.1 on "This PC" I do not see my tomtom or sd card drive letter.


I want to install new map. My Tomtom model map is VIA 125 when I connect it with MyDrive software to update map.
But here in USA same model is VIA 1525 I guess.


How can I fix the issue and see my sd card so that I can install new map?

Hello @arman960

Your Via 1525 is a Nav3 device.

To install a new map, the best tool is TTActivator, directly in the 4Gb internal memory.

Installing a bigger new map in the SD card (8Gb or 16 Gb) will first need to save the map on your laptop hard disk.
Then in addition use RLink Explorer (and some skill) to transfer the map to the SD card.

Have a search in the forum : Tutorial

The prolem is when I hook up Tomtom, it shows Tomtom is connected but my computer does not assign any drive lettter for Tomtom so that I can update the map.

TTActivator even does not show the Tomtom drive letter. In order to update with TTActivator, I need to show up tomtom.

Hello @arman960,

I use everyday my Via120 (4Gb) with a 16Gb micro SDHC card.
If connected to my Windows laptop and switching the Via120 on, nothing appears in WindowsExplorer ... because it's a Linux file system.

As opening TTActivator, the upper line "Source" displays "Tomtom Via (Nav3)" but no SD card.
Below appears a new tab "Nav3/Nav4 tools" : there is all you need to download a map to the internal memory or to a file on your hard disk.
To install the new map on the SDHC card, you will then need RLinkExplorer to transfer the downloaded map from your hard disk to the SDHC card.

Everything was in the tutorial.

Thanks you much for the help and reply. It worked the way you said. I removed the 16GB SD card. I tried to installed USA map only.

But it said I do not have 3.79GB to install it.

My question is how do I install USAap only , I thing you said this Tomtom Via 4GB. I also deleted the previously installed map that was internally.

Before any map download, check first if a metacode 1155-nav3 is published : Known metacodes

To fit 4Gb internal memory, you could choose a smaller coverage of USA : Western USA, Northern USA, Eastern USA, or Soutern USA.
All are under 3Gb each.
Have a look at the post "Worldwide coverages and search" : Coverages

Once you will have learned how to master RLinkExplorer, it's really easy to transfer larger maps to 8Gb or 16Gb SDHC card, downloaded first as a file on laptop or hard disk.
Several viewings of "How update patch nav3 devices" : Tutorial were usefull to me ...

You could then run a full "USA Canada and Mexico" (4.49Gb) !

Thannks for the reply. I installed US South Atlantic map with. But the map is not loading when I try to select the map. It reboots and ask me to select map. Map is installed but not loading. Just tells me to selct the map installed it properly.

You have to validate some options in TTActivator

"Tools" : Update Meta

"Nav3/Nav4 Tools" :
- Install Patch if not already made, one time,
- Upload Meta to Device,
- Reboot Device.

If you need to delete old maps from internal memory, all of them will be deleted and you'll have then to patch navcore again.

Thanks you. Worked very well. I like the interface also.