I’ve got a native 4K JVC Nz7 projector Apple TV and kaleidescape are all able to do 4k@60fps but Roku doesn’t even though the projector supports it cable and Denon AVR do too. Roku limits at 4k 30fps but then every time I come back to it it adjusting to 1080p hdr
Have you tried setting your Roku's Display type setting to that needed for the projector instead of relying on the "Auto select" setting?
From the Roku home screen, Roku menu path Settings > Display type
When you change the Display type to a new setting it runs you through several screens:
A screen where you can choose from the available options on that device.
A screen where it analyzes your choice to be sure your tv supports it, then gives the option of trying that choice if you wish.
A screen with a countdown timer and two choices: Yes, screen looks good No, I will choose a different setting The "No" option is highlighted by default. To keep the screen resolution you're currently trying, you need to arrow up to the "Yes" option and click on it before the timer runs out.
Roku Community Streaming Expert I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well. If this post solves your problem please help others find this answer by clicking "Accept as Solution.".
Streaming Stick 4K+ 3821 | Streaming Stick+ 3810 | TCL Roku TV 43S245/C107X