I've grown tired of updates that introduce new bugs and would like to stay on my current software version. This method works also on Edge devices:
Create an empty file with defined size and save to your fenix 5. This empty file will take up most of the free space on the device so that the update file GUPDATE.GCD cannot download to the device.
In my case, GUPDATE.GCD is 3.9 MB. My fenix 5 has 47.8 MB of free space. I need to put a 44 MB file on my watch, so there is insufficient room to download the update file.
Windows: https://ccm.net/faq/15846-windows-7-create-and-empty-file-having-a-defined-size
Mac: http://osxdaily.com/2013/05/31/create-large-file-mac-os-x/
