GPSrChive Discussion Forum

The 66 doesn't want to connect to the laptop it locks up when the Saving all waypoints message appears and only gets as far as 1%.

So, needless to say, I can't get to Flash the RGN file.

I do not think you are following the directions properly....

We have a 66st here v4.80 and were able to flash older firmware RGN in less than one minute total, beginning to end.

You have to follow the directions given precisely.

This is the longest I’ve known of Garmin not to put it on their main update site
Maybe these screen flicker problems are the reason.

It took several attempts to get it going right and turning the 66 from a brick to something now useful.

Thanks very much for your help.

Now I'm trying to figure out how to stop the updates being automatically updated to the GPS. The first thing is to uninstall both Garmin Express and Webupdater as I feel they could be the culprits.

Garmin express, yes. But this app can be turned off instead of allowing it to run in the background.

WebUpdater, no. Only runs when you tell it to, never in the background.

Garmin connect on your mobile device can send updates via blutooth, and Wi-Fi enabled on the GPSr will allow the device to download updates also, so you may want to disable these until a workable update is released for the GPSMAP 66s/st.

Please keep posts in this thread on topic (GPSMAP 66s/st Firmware v4.80).

Thank You.

Hi team,

just saw couple of posts above about device freeze after updating from 4.20 to 4.80 with "Software loading..." screen. My experience is similar and after trying all I was requested by Garmin support to send the device for an exchange. Today I got the new device from service and what would you think - it has the same issue
Seems to be for some devices we will need to wait for 4.90 or 5.0 update to be able to have new firmware working.
What is strange - I did not get any info from support that it is known issue and I need to wait.

Just wanted to let you know and calm down those who has the same issue. You are not along. I keep 4.20 at the moment and informed support.

Yes, the GPSrChive > GPSMAP 66 > Firmware page makes this abundantly clear!

Those who have updated their GPSMAP 66s/st to 4.70 or 4.80 and have an unresponsive unit can still recover the unit by installing firmware 4.20 using the RGN Firmware Installation process (also available from that same page).

Good news! Garmin support had me try out a 5.00 beta, and it fixed the issue of being stuck at "Loader Loading" that I was getting when trying to update to 4.80. The update applied without any issue

That's good to hear!

Probably will be another new update available soon for everyone...