Only one model of Roku responded to power command, that was Roku 4. The power key on the roku remote is strictly for TV's, never the roku.
If you want power key to no longer control your tv, of course the volume keys won't work either, go to remote in the settings menu, go to remote in use, then program tv, tell it any other brand then yours like Toshiba, lie to it and say the first code worked.
Edmund Roku Community Streaming Expert
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