Garmin watch - updates without connecting to the Internet “offline”

cross-posted from: https://lemmy.ml/post/27209720

I bought a Garmin Forerunner 255 watch that I want to use only with Gadgetbridge. There is an old software version on the watch and I want to update it and I don't want to connect it with Garmin Connect or Garmin Express app?

I have looked for the possibility to do an “offline” update but have not found it. Maybe the community will help?