Thread: City Navigator North America NT 2013.20

Originally Posted by GeekDad66

Okay, I am way confused with map update. It might be because I read a lot of the earlier posts which are now obsolete. I have a 755T and I downloaded the files that apply but I am not clear as to what/how I should use. The following are my questions:


Q1: Is there a limitation on the SD card size that can be used? I was going to use an 8 GB card but I am not sure my 755T will recognize.
8 Gig is fine, in fact I'm using a 32g imy 755T

Q2: I was hoping to put the update on an SD card so as not to affect my existing configuration. From the tutorials ([Only registered and activated users can see links. ]), it appears that once I use the SD card, the unit will not work properly if I remove the SD card. Is this still true?
That is true. The GPS reads files in real time from the SD so the SD must be inserted to work. You also don't need to use an SD (YET). The 3 files you need "gmapprom.img", "gmap3d.img, and *.JCV will still fit in the internal memory of a 755.

Q3: Some of the tutorials reference Basecamp, MapSource, MapInstall and HomePort. It is my understanding that some of these are no longer supported from some of the threads. Not supported but they work fine For the unlocked images, can Windows Explrer simply be used? Absolutely not. Windows explorer is used for copying the img files it can't display them. Someone with more experience may want to clarify the obsolescence issues upfront in some of the tutorials and indicate the current preffered method. I don't think there are any issues. They all work, it depends only on what you are trying to do. Each of those tools has different capabilities.

Q4: I took the original MapSource data and used one of the unlockers (NOTE that GarminUnlocker.exe which uses the .tdb file did not work for me) as Mapsource and MapInstall were saying it was locked (yeah duh, I realized that afterward). I ended up using MapInstall and put on my 8 GB SD Card. I see it created a single file (gmapsupp.img) and that's where the duh moment kicked in (unlocked map is already this file). I have not put SD card in my GPS yet. Could I have simply copied the unlocked gmapsupp.img file directly to my GPS? Yes. I don't currently have a gmapsupp.img file on this GPS and I don't think there would be enough space. The name "gmapsupp.img" is typically for a second map and it's true, there is not enough room. The solution is to put it on SD OR put it in the GPS by replacing you original/defauly map named "gmapprom.img" (by naming convention).

Q5: From the file structure of my GPS unit, it looks like the GMAP3D.IMG file goes in the Garmin subdirectory since it is already there. A quick check of my 755T does not show these files at all:
D3060070A.JCV

D3153070A.JCV

D3397050A.DB

D2656080A.SID
D3157060A.SID
D3398050A.SID
D3406050A.SID

0464H4AO.SRX
0464H4AO.ASR

The only file of the above list you might see is a .JCV file and it may be a different number. You should find it in the 755 here:
x:\garmin\JCV\DxxxxxxxA.JCV
None of the other files types are supported in a 755T
How/where would I put these files?

Q6: From what I see, can I simply copy the gmapsupp.img and GMAP3D.IMG files to the Garmin directory using Windows Explorer and consider the update complete? See below

Sorry for my confusion, I may be overthinking things.

Lets keep it simple.... To update a 755 only 3 files are involved and they are a matched set with each release.
1. gmapprom.img the detailed maps
2. gmap3d.img the 3D buildings (this is optional for giving you 3D buildings view if enabled and it really slows down the drawing speeed on a 755
3. DxxxxxxxxA.JCV is the Junction view file, also optional. You will not see any junction view photos without it.

gmapprom.img and gmapsupp.img are interchangeable names. In other words you name/rename this file depending on where you use it.
gmap3d.img and gmap3d1.img are also interchangeble names. In other words you name/rename this file depending on where you use it.

To update a 755 internally you need these names and paths
x:\garmin\gmapprom.img your maps
x:\garmin\gmap3d.img your optional 3d buildings
x:\garmin\JCV\DxxxxxxxxA.jcv your optional junction view files

To update a 755 with the new maps on SD you need these names and paths
x:\garmin\gmapsupp.img your maps
x:\garmin\gmap3d1.img your optional 3d buildings
x:\garmin\JCV\DxxxxxxxxA.jcv your optional junction view files

Note... gmapprom.img, gmapsupp.img, gmap3d.img are files you would be downloaded. You may find LOCKED or UNLOCKED versions of these files. Download UNLOCKED copies if you can find them. If you get LOCKED files, download the "GImgUnlock.exe" tool and unlock them yourself.