I made a video tutorial for how to flash the ffu file without updating to windows 10, also works on windows 10 machines, sorry for the quality of the video.
download the Windows ADK RC for Windows 10 its at the bottom of the page
https://msdn.microsoft.com/en-us/window ... 13721.aspx
Video tutorial
https://www.youtube.com/watch?v=25Kse5h ... outu.be&ac