Thread: Garmin GMA protection and the "Unauthenticated" status

@atomiktd: I have lifetime maps for my 1300 and I wrote the how-to for myself. I decided to share the how-to after I put it together but made it clear in the introductory paragraphs that I had a lifetime map subscription and based the tutorial off that assumption. The Maps sub-forum has all the maps you may need or want and I have placed a link to the forum in the notes section.

Has anyone been able to disassemble and look at the details of the code for these GMA files ?

Is there a way to generate a "legitimate" GMA file if needed?

I ask because I suspect that Garmin has some updating schemes that they just started, that "may" require you to log onto the Garmim server to get an update.. but the server will look for a bonafide GMA file to be present on the GPS unit or SD card before it sends any updates.

I can't say for sure... but it's just a suspicion I have at this time about this GMA file check.

Originally Posted by timp4411

Has anyone been able to disassemble and look at the details of the code fro these GMA files ?

I tried out of curiousity ages ago by changing the ext to .txt to see if info would be visible in notepad like with .unl changed to .txt. Not the slightest bit suprised when the only readable info was "GARMIN GMA", followed by unreadable symbols. Lost interest after that.

Is there a way to generate a "legitimate" GMA file if needed?

Wouldn't think so.

I ask because I suspect that Garmin has some updating schemes that they just started, that "may" require you to log onto the Garmim server to get an update.. but the server will look for a bonafide GMA file to be present on the GPS unit or SD card before it sends any updates.

I can't say for sure... but it's just a suspicion I have at this time about this GMA file check.

Well, i hope not...brrr! But best to always leave your legit preloaded map only on the unit with its .unl & .gma, and take out the sd containing anything else before updating. That's good practice anyway in my opinion.

Originally Posted by stuart1974

...Suppose i have 100 GMA files for same map licensed on 100 SD cards and i have the serial numbers of the SD cards, is there a way to generate a keygen to make GMA, i mean solve the variables...

Unlike *unl files, the *.gma files are unable to be 'manufactured' by a keygen such as Jetmouse. Modern unlockers overcome the GMA on *.img files anyway: [Only registered and activated users can see links. ] and more recently this pearl: [Only registered and activated users can see links. ].

No, only because it's not known at this time how many variables are actually involved in creating the GMA file. Besides, it's simpler and less annoying to simply unlock the map once using the combination of Mapset Unlocker and Garmin Image Unlocker then copy the resulting file to each card. No GMA file needed when using that combination of programs.

EDIT: I see Neil beat me to the punch.