Thread: Garmin Montana 650t GMA protection work around.

Originally Posted by itcheybum

I don't know if anyone else has had the problem where you get the "unable to authenticate maps etc" message when loading but the latest Firmware update to 5.9 seems to have fixed the issue.
There seems to be a million work arounds with keygens and the like but this is by far the simplest way to do it:
GCD Update Procedure

Use the links in Firmware History to download the zipped file for the version you desire
Unzip the downloaded archive and extract the gcd file
Rename the gcd file to gupdate.gcd
Connect the Montana to your computer and enter USB Mass Storage Mode
Copy the gupdate.gcd file to [Montana]\Garmin\gupdate.gcd
Disconnect and reboot the Montana
Once the update is completed, the GPSr will delete the gupdate.gcd file


So far no other stability issues so only time will tell.

Do you Downgrade the Firmware ?

Montana software 5.60 was buggy, news here
[Only registered and activated users can see links. ]
and following.
Oregon 600 had the same, then fixed.
[Only registered and activated users can see links. ] post 127 and following.
Some devices got bricked too with these firmware. Both (Montana and O600 sw have been withdraw from Garmin server after few days)

Montana (WebUpdater) software version 5.60 (withdrawn by Garmin on Feb 3

Be careful to reverse to buggy previous firmware.
Newer Montana and O600 firmware don't have protection, so we don't need any workaround actually.