format the usb to fat32, and if still using the ez method, make sure you are not in a usb.3 port, but i strongly suggest you use the flashback/rog port option. next, rename the .cap file to reflect your mobo:
i use the iv gene board, so i rename my bios updates to R4G.CAP., then using the rog port, press the flashback button until it starts blinking, and let it go until no lights are blinking, on the board or usb drive. it doesn't matter which release version you have when renaming using abbreviation re your board version/bios update version when using the flashback/rog port method, plus the flashback method is a bit safer/reliable...
Asus Rampage IV GENE
i7 3930k @ 4.8 24/7
custom loop
16 gigs Trident X
HIS HD7970
2x OCZ Vector 256gb raid0 via UEFI
Crossover 27Q
Win8 pro