I have the exact same issue. Brand new cube orange on ADS-B carrier board. Using above, I was able to flash the latest PX4 1.12.3 via QGC using the usb port on the cube itself and not the carrier board. It shows successful and plays the right tones. My issue is after the flash. No matter what I do with Windows 10, device manager still shows Cube Orange Mavlink (COM3) as “A device which does not exist was specified.” As such, QGC cannot recognize the cube so I can’t set parameters. I have uninstalled drivers, used MP to clean drivers, reinstalled and I am out of ideas. Thank you for any suggestions you can throw my way.
EDIT: I would also like to add, if I flash ArduCopter then everything works as expected, no driver issues at all.