Awesome, thanks. That's actually exactly what I did before from an Ubuntu machine with a USB Wi-Fi dongle. Did not get beyond the first sending phase although I could hear the device restarting and could see traffic via tcpdump. So, on reading about your success, I dug out an older Raspberry Pi...
Does anyone have any success in getting tuya-convert to work with the latest (R199) UL-P01W?
Alternatively, opening it up and seeing whether it has serial exposed for Tasmotization? It seems like quite a nasty thing to open up, so any hints from someone that has already done so would help... :)