RMA it then. Sounds as if you have done it all properly.
You do know 2x2 requires different settings for the ram then 4x1 or 2x1 right? You need 52-62 or more for refresh to act, and +1 or more MCH voltage
When you say it wont keep your multi what multiplier # are you trying to use? And do you have TM2, EIST, C.I.A.2, and C1E disabled?
And when you DO flash (please do not use @BIOS) do you load optimized defaults, then save and apply and reboot before making your changes? If no you MUST, if you dont do this, then please try a flash again and do it properly by loading optimized defaults first and save and apply that and reboot then make any changes you want