I'm not Chuwi employee, but I will try to help you.
BIOS:
1. Download archive https://www.dropbox.com/s/tb8csv ... 03%20BIOS.rar?dl=0.
2. Extract archive.
3. Copy everything from "Hi8 2016 03 BIOS" folder to the root of your USB drive.
4. Boot from USB. (press Esc while your tablet is turning on, then select Boot manager, then select your USB drive)
5. You will see flashing utility doing some magic, then your tablet will reboot.
6. Congratulations! ImagenExternaRotahttp://forum.chuwi.com/static/image/smiley/default/smile.gif
Also, I suggest you to watch this video
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despues responden que funciona... el archivo ese de dropbox es el mismo que el de techtablets