GMA file is a digital certificate bound copy of a license tying your device to your map , this means you need a GMA file to unlock the product.
GMA file if present ,should be in the system folder on the device and in C:\Users\adm\AppData\Roaming\GARMIN\Maps
and has a .gma suffix, you could regenerate it by logging in at my.garmin.com, finding out the product code of your map-
The Oregon new firmware checks for this unlocking certificate
You shell have to use fast unlockeror use mapsource gmap versions unlocked
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