Version bought in December 2020 cannot be flashed with tuya-convert, it has to be pried open.
Remove the two security screws on the backside. Pry open from the top of the connector rounding on the backside. Two plastic clamps holding it together at the top and at the bottom. A bit of force is needed. When opened, remove the four screws from the PCB and the soldering points are clearly marked and accessible at the bottom PCB.
Same template used as for the indoor version WIFIP120FWT used and working flawlessly