Too late....I am now a 4306 owner and I dont see anything about firmware. I do know that denon usa offers firmware downloads from their website...so I am hoping that if there is an issue they will allow us to do it ourselves. I have not noticed the problem myself just yet...but I am not running hd-dvd or blu-ray through hdmi. I will be soon and report back then.

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Denon 4308
M80x2,VP150,EP600,4xQS8