It might work on the X99-A but mine is a deluxe and both ASUS and experience have both confirmed that SATA SSDs (HDDs are fine ofc) will NOT work with the X99-Deluxe.
How do I update the BIOS if I don't have Windows installed yet?
Use this method : http://event.asus.com/2012/mb/USB_BIOS_Flashback_GUIDE/