Hi,
just to notify that things are sorted out now.
Firstly this flashing issue not being able to flash with arduino anymore-
Just revert to your original arduino version when you had bought the printer.
Regarding my Z steps issue-
It seems long ago, when we flashed the wrong firmware (TAZ 5 rather then TAZ 3 I needed), we made some LCD changes and hit “store memory” option
Because of that, it keep the wrong z steps per mm inherited from TAZ 5. And no firmware ever overrode it. I had to manually enter LCD (by accident) and change those values manually to steps per mm which are adequate…
funny 