Re: Using Roku 4K remote to turn off bose soundbar
That isn't an accurate enough description of your remote. My Ultra is 4K, but it's older and doesn't have a power button or IR support for other devices. Newer remotes have one or both. If your remote has a power button and support controlling other devices with IR, there should be a code that works. If it doesn't have a power button, then I believe the answer is no.
Dan Roku Stick (3600), Ultra (4640), Ultra (4670), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.