How do you stop automatic firmware updates forever and ever

What firmware do you want to have? And why?

I think, but not sure , if you dont connect to the Gc thn you will not have the update, but you have to test

I remember that a while ago, I have tried to edit an xml inside garnin in order to trick that I have bigger version , but i did not work, but this shoud be the ideea 

It was back in the days of the Edge 1000 - that's how I solved this problem for a few months until there was a stable software available:
-copy any small text file to Edge\Garmin
-rename the file to GUPDATE.GCD
-mark the file read-only

The Edge 1000 had recognized that this was not a valid update file and he could not overwrite it with a valid one either. Did not ask anymore. To end that state: I unlocked the fake updatefile from read only and deleted it.

I do not know if this still works today - I prefer not to test it on my Edge 1030 
To point out the risk: if you are not able to unlock the file in the future - yoou’re fu@&ed. 
So, test it before with a testfile. I have had no problem. 

Anyway, I point out that everyone does it at their own risk.

good idea mcinner1, I just put that file on and the 1030 turned on without an issue. I'll follwup if I run into issues or another prompt for a firmware update

What version do you want to keep?

v 10.20 works fine and I don't want to possibly have issues with a connectIQ data field from a company no longer in business.

To follow up: the locked gupdate.gcd text file did not work. Garmin Express just put the update, of the same exact name in place.

Strange...
Wen you locked the file as "read only", did you try to delete it?
Should not be possible and also not possible to rename it.
So... very strange...

But thanks for information anyway.