Hi, i have the same problem here, my tablet is not reacting at all.
I tried to connect a mouse and a keyboard, and the tablet is delivering power only to the mouse.
When i connect on my computer nothing happen ( the computer and tablet)
I tried all button combo, but none of them worked.
Sorry for my english, i’m french
Video : https://www.youtube.com/watch?v=GTKhQWm4Dx0&list=PL9dyNDvx7DfiCKczcqms2eI794HtFOS5q
