As regards the proposed me above an install file. This is a compiled install file of latest July 2016 Anniversary Windows 10 Redstone Release Edition.
It's only for Chuwi Hi12 Dual Boot tablets with serial numbers higher than 451603XXXXX.
It's only for a clean install Windows 10 Anniversary Redstone Release Edition and can not be used to upgrade your Windows. All current Windows partitions will be replaced with new. So you need to move all your necessary files from your current system first. This concerns Windows only but not Android or Remix OS.
As a result, you will got a new clean Windows 10 and left your second system (Android or Remix OS) intact and unharmed.
You can compile your own install file for yourself. All you need is some motivation Maybe some skills to use command prompt, and to know some DISM commands. By the way, you can install En-US version and then download and install the German language pack.
What else do you need ? On 1511 version pressing VOL UP or VOL DOWN made sound louder or silent. Now on 1607 pressing VOL DOWN is generating CTRL+ALT+DEL keyboard shortcut and i'm getting screen with lock/logout/task manager screen. VOL UP i making screen gray but nothing happens. Looks like soundcard driver issue ....