Creat a bootable USB of windows 10 on ubuntu [duplicate]
Not specifically an Ubuntu question:
UEFI only USB key, just extract ISO ( 7 zip or similar) to FAT32 formated flash & set boot flag.
How to create UEFI-only bootable USB live media?
Windows 7, 8, 10 BIOS or UEFI boot installer from Ubuntu More details:
http://onetransistor.blogspot.ch/2014/09/make-bootable-windows-usb-from-ubuntu.html