I have a model 4660X - ROKU ULTRA running 10.0.0 - Build 4209-46. It came with a remote that has voice control and replaceable batteries, It stopped functioning the other day so I replaced the batteries and pushed the button (beneath the battery cover) to re-pair the remote to my Roku. A pop-up arrived that started a countdown clock (at 117) and my remote started pinging with the sonar sound. The pop-up required that i press any button on the remote to stop the pinging thereby connecting the remote. I did and the pinging stopped for about 2 seconds, then the pop-up reappeared and the pinging started again. I pressed any button again , the pinging stopped and the pop-up disappeared ... for about 2 seconds, when the whole thing started over again. It keeps re-initiating this "find remote" procedure even after a system reset, unit unplugging and battery removal/replacement. The constant re-activating makes it completely unusable and I have since disconnected my ROKU entirely, and am just using an antennae. HELP #4660
I didn't think you needed to "re-pair" the remote after a quick battery swap, I haven't needed to do that with my streambar.
For now, use the Roku app on a mobile phone to control the device. Must connect to same WiFi to do this. May be able to reinitiate the pairing using mobile app, delete previous remote details.
Ultra should work with IR based remotes as well as wireless radio. Cheap clones available on internet, or higher end ones like oneforall (e.g.7935 which is compact, or ones with full number keypads).