Thanks for the tip, but I made this swap back to the ArduPilot hunderd times now I think So this will not solving the problem.
Also tried to uninstall COM drivers via W10 Device Manager, tried without them and then also tried to install back UAV driver and try all the round again. There seems to be deeper problem. Can you confirm that your PixHawk Cube Orange
Sorry, I actually just returned my cube orange because it did not quite fit my needs (for a separate reason) so I can’t really check at this point, but I am completely certain that at least I was able to flash PX4 and arm. I would guess it’s a driver issue of some sort. Did you do the ‘driver clean’ step as suggested in the cube documentation? (see link above)