Sorry if this is a stupid question. Anyone know exactly what a gma file is? as in 'gmapprom.gma'

Is this an authentication file? Is it tied to the map itself, or can you add new maps without having a new gma file?

@nfwego This file and also another one .unl are used by your device that you didn't mentioned which is most possible to unlock your map in order to work.
If your device is a new one and not patched firmware definitely you need them to be present on your device otherwise your installed maps will not work.

@kolokythas

Thanks for the reply. So how do I get patched firmware? My device is not new. its from 2012. Its on my car.

Or better yet is there a way to open the gma file and modify it? Jetmouse helps with the .unl file but is there a way around the gma file?

So what is your device and firmware? You may try to see if can recognize unlocked files and better solution if you still need your current map to unlock it with Unlock software.

My device is a Chrysler Rhb15 radio/garmin head unit. My garmin software is version 6.22

I have tried unlocked files as well as locked files with jetmouse code placed in the *.unl file.

Since you have a very good knowledge about this device why you don't share with us also part of this explaining the difficult update procedure?
Thx!

The device has a usb port on in to update maps. I bought an update from Chrysler/HERE and updated it, but the update they sell is basically 2015.40. (They call it 2016) So I am trying to update to 2017 maps. I am using the same usb drive replacing the gmapprom.img files and jcv files and even changing the .unl file to have a proper jetmouse code for the IMG file. When I try to update it says Update procedure failed. Im pretty sure its the gma file that is causing the issue.

@nfwego I don't have such a device so i cannot check the procedure but i will transfer to you what others have done in order to update it!

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thanks. I may try that again...but I have been down that route already and it didn't work. I think it has to do with which radio you have. If it was made before 2012 it will work, if it was made after that it wont. I am currently on radio firmware 50.00.01, and garmin software 6.22. From past attempts I have copies of all that firmware I can try again, and I will report back if I do.

But I really think it has to do with figuring out how the gma file works. Is there any way to open the gma file so its readable? When I open it it is a bunch of weird characters.

As you can notice our friend say that you may choose to update only the garmin software to the others you just say no! Please try !

I followed the steps above perfectly. When I get to step 8, it will not allow me to update the garmin software and says my current version is newer and then skips ahead to asking about the radio firmware. it never gives me an option to say yes to downgrading to the garmin 3.0.

Can you copy the gupdate.gcd from your device and send it to me?
I can think two possible ways to overpass your problem but i need your file.
If you cannot extract it from the device send me this file from your last update.

I cannot copy the file from my device but I can from the software update CD. Now if I can just figure out how to send a file on here.

I couldn't figure out how to attch a file to a PM so I sent you a link to the file on my dropbox.

BTW...thanks for taking the time to help. I do appreciate it.