I don't think there is an update- BUT, don't worry, the hdmi board will die soon and you'll end up buying a Yamaha RX-A700 like me. The Yamaha is great and (so far) GLITCH FREE.
I loved the 706 until it started having handshake issues. Then, it was all downhill.
By the way, my dad still has my 20 year old Onkyo Receiver and it works great. All their recent stuff breaks. I have a DX-7555 Cd Player, very lightly used, and half the time it won't read CD's. Unreal. I've lost all faith in Onkyo's quality control.