Garmin gpsmap 66s firmware update problem

Discussion related to the Garmin GPSMAP 66s/st GPSr
speedser
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Joined: Thu Aug 28, 2025 1:52 pm

Garmin gpsmap 66s firmware update problem

Unread post by speedser »

I have such a problem, in the navigator on the information tab it says that the firmware version is 9.60, when connecting the navigator to Garmin Express it shows that the firmware is 11.60 and no updates are required. I contacted Garmin technical support, but they did not advise anything except to reset the device to factory settings and still after these operations the problem remained (((.

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GPSrChive
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Re: Garmin gpsmap 66s firmware update problem

Unread post by GPSrChive »

Please send a copy of the GarminDevice.xml file from the Garmin directory to:
@
JungleJim
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Re: Garmin gpsmap 66s firmware update problem

Unread post by JungleJim »

I had the same issue once on my GPSMAP 67, where the version numbers did not match after an update.

The solution as advised by Garmin was to copy the firmware update file to the Garmin folder of the internal storage of the device, and create an empty file called FORCE.TMP in the same folder. Then reboot the device.

This will force an install of the update file (GUPDATE.GCD), independent of the actual version of the update file (yes it can also be used to downgrade a device).

Not 100% sure if this procedure will work on a 66s, but worth a try.

Only issue is where to get the correct 11.60 firmware update file. I’m afraid I can’t help with that, but maybe someone else can.

And of course this procedure is at your own risk.
Current: GPSMAP 67, inReach Mini 2 - Previous: inReach Messenger, GPSMAP 66sr, Oregon 700, Dakota 20, Edge 1040, Edge 1030 Plus, Edge 1030, Edge 520 Plus, Edge 520
speedser
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Joined: Thu Aug 28, 2025 1:52 pm

Re: Garmin gpsmap 66s firmware update problem

Unread post by speedser »

Thanks for the advice, I did everything as you said (I found the firmware for the device 10.70) but after rebooting nothing happens, the navigator works and does not update.
Przekątny
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Re: Garmin gpsmap 66s firmware update problem

Unread post by Przekątny »

JungleJim wrote: Thu Aug 28, 2025 4:57 pm This will force an install of the update file (GUPDATE.GCD), independent of the actual version of the update file (yes it can also be used to downgrade a device).
I've updated the device to a newer version multiple times, older versionm, updated didn't require an additional file.

The problem is with updating to the version installed on the device ( to the same version).

The device had the same software version and the update file was the same version, so the service recommended an additional file to update it again.

In GPSmap 67, there's no update via a file with the .GCD extension; it's replaced by a file with the .GSP extension. The file name has been preserved.
Przekątny
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Re: Garmin gpsmap 66s firmware update problem

Unread post by Przekątny »

speedser wrote: Thu Aug 28, 2025 1:55 pm I have such a problem, in the navigator on the information tab it says that the firmware version is 9.60, when connecting the navigator to Garmin Express it shows that the firmware is 11.60 and no updates are required.
I understand that it is irritating, but I wouldn't worry about it, there will be a new update and maybe it will go back to normal.
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GPSrChive
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Re: Garmin gpsmap 66s firmware update problem

Unread post by GPSrChive »

Please try next the RGN firmware install found at GPSrChive > GPSMAP 66 > Firmware
speedser
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Re: Garmin gpsmap 66s firmware update problem

Unread post by speedser »

Przekątny wrote: Thu Aug 28, 2025 10:49 pm
speedser wrote: Thu Aug 28, 2025 1:55 pm I have such a problem, in the navigator on the information tab it says that the firmware version is 9.60, when connecting the navigator to Garmin Express it shows that the firmware is 11.60 and no updates are required.
I understand that it is irritating, but I wouldn't worry about it, there will be a new update and maybe it will go back to normal.
The thing is that the expedition mode on this firmware version 9.6 does not work properly. and I cannot update the firmware using standard features
GPSrChive wrote: Fri Aug 29, 2025 2:44 am Please try next the RGN firmware install found at GPSrChive > GPSMAP 66 > Firmware
Thanks for the help, I did everything according to the instructions, but I have some questions, is that okay?
Firmware file 10.70


Verify the HWID displayed in the RGN_Tool window matches your GPSr HWID
GPSMAP 66s, 66st HWID = 3028
JungleJim
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Re: Garmin gpsmap 66s firmware update problem

Unread post by JungleJim »

speedser wrote: Thu Aug 28, 2025 5:51 pm Thanks for the advice, I did everything as you said (I found the firmware for the device 10.70) but after rebooting nothing happens, the navigator works and does not update.
Ah that’s too bad, apparently the procedure does not work on the 66s. Was worth a try!
Current: GPSMAP 67, inReach Mini 2 - Previous: inReach Messenger, GPSMAP 66sr, Oregon 700, Dakota 20, Edge 1040, Edge 1030 Plus, Edge 1030, Edge 520 Plus, Edge 520
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GPSrChive
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Re: Garmin gpsmap 66s firmware update problem

Unread post by GPSrChive »

speedser wrote: Fri Aug 29, 2025 5:20 am
Thanks for the help, I did everything according to the instructions, but I have some questions, is that okay?
Firmware file 10.70

Verify the HWID displayed in the RGN_Tool window matches your GPSr HWID
GPSMAP 66s, 66st HWID = 3028
Interesting, we see that too.

If this procedure fails you, save all important data from the device, then install an older version, like 7.20 or 7.60, which will reset the device completely and clear all user data. Once the older firmware is verified, Garmin Express should offer you the most current version, or you can manually install it yourself.
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