Your original Ultra 4640 remote didn't have tv IR on board, what it has is Roku CEC volume commands preset, that can't be changed. Your new remote only has tv IR on board, when programmed via on screen menu. There is secret menu to switch from IR to CEC, we can't post it. CEC doesn't care if it's a TV or AVR, or what brand it is, only that the device accepts CEC signals.
Edmund Roku Community Streaming Expert
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