This was a first / near first hit on google searching for backing up of firmware on a mainboard. Want to point out as mentioned in the thread. Use of :w: Is "write" to the Arduino / mainboard memory NOT "writing" / "backing" it up to a local file where avrdude is running. This is what I did to backup a CR-10 (non S) Marlin 1.1.9 firmware I had installed on it. I'm trying out 2.0.0 BF with a Bby weinberg - Sanguino(lolu)