If I get time and I can find my hdmi cable I’ll do a test when I get home today.
Edit – just did a quick test and like you nothing in windows. In android it seems to know it is connected in the settings but nothing displays on the tv, also it made the tablet screen go black a few times and become unresponsive. So not looking great. Maybe that new bios will fix it
I fixed this by cutting off 1-2mm of the plastic/rubber around my HDMI cable plug. Had no view while trying 2 different cables. After I cut the rubber/plastic it lodges slightly deeper into the tablets HDMI port and then it works. Give it a try!
I hope you dont encounter the sudden blackouts in Windows10 that myself and many others do. Running on battery it suddenly shuts down when it reaches 40-50%.