Hello, i had the same problem with my Onda V919 3g Black and Gold Edition dualboot Device.
After i tried to Reset my windows 10 installation, the progress stops at 64% and the device restarts.
So i downloaded the Windows 10 Images for Onda V919 dualboot devices from http://www.ondaforum.com/files/ and make a fresh windows install. After that all was fine.
Regards