I got 2 X16 Ultra from gearbest. One of them stuck in a bootloop.
What I´ve done:
Start the Tablet in Widows mode, it was very slow, so I restore windows. After 5% it stucks and nothing happend anymore for a few hours.
Restart the tablet in Windows recovery and turn restore of. Windows doesn´t start anymore since that.
Start in Android and press switch OS to Windows. Bad Mistake! The tablet stuck in the bootloop. Reset very often.
Start the Bios to activate start from USB. There is no start from USB. But I activated FAST BOOT. Next bad mistake.
I can´t get into the bios with keyboard (The one that came with neither usb keyboard). The hidden onscreen keyboard pops to fast out, so I can´t press del or esc.