Did you try re-pairing remote to roku? Unplug the power from roku, plug it back in when roku starts bouncing start pressing and holding the pairing button in the battery compartment, when it stop bouncing release for a bit and start pressing again until you get confirmation its paired.
Edmund Roku Community Streaming Expert
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I followed you steps and remote worked for a while but now will not respond again. I repeated powering off and re-paring but still doesn't work. Having to use my iPhone which is ok but would like to get remote working agin.