There is still a small possibility that the windows only version is exactly the same as the dual boot version with just a different bios. Why else would chuwi offer to send them to the factory? I think they just don’t want people to update the bios themselves. There is just too much that can go wrong. (brick tablet etc.) You would also have to store the windows key and reprogram it somehow, which needs to be done in the factory I guess.
It’s just strange that the newer single boot windows version has a dual boot bios(5.011), why would you program a dual boot bios if you have another bios that is working just fine? I think the hardware might be the same, just some other software stuff Chuwi don’t want to admit maybe. (I am hoping for that :P)