I just purchase a Roku Premiere streams HD 4K HDR. Prior to this Roku I had a Roku XD-S model 2100x. I have hooked up the new one but the picture I get from Roku is too large for my TV. I have a Vizo 55 inch TV. I can't read the instructions on the Roku screen because it is so large it is out of the viewing area of my TV. Hopeful someone can tell me how to correct this. I can't seem to get anyone from Roku on the phone.
Roku players do not have screen size adjustments. But to my knowledge, all modern TVs do. There might be a button on the TV remote labeled picture size, or aspect ratio, or it might be somewhere in an on-screen menu. But you should be able to get the image size set correctly with such a menu.
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.