These are some notes about this dual OS tablet.
DO NOT do a Windows refresh. It stalls and Windows becomes unbootable.
The tablet can boot from a bootable UEFI external USB drive for Windows installation.
In theory, a clean version of Windows should be installable, drivers can be found at techtablets.
Official images from Teclast can be obtained at their pan.baidu repository (images updated on 2016-03-11 as of this writing) but download speed is terrible at least in the West. Mirror at MEGA provided by Bram Pribadi at this thread.
The official image is just a RAR archive of the installation media contents. Copy it to a clean UEFI-bootable FAT32 drive and it should work.
Fire installation by entering the BIOS (from power off, Volume UP + Power), go to Save & Exit and select to Boot override with the flash drive (listed as Android…-Your drive name)