I ordered a Roku 4K+ from Amazon for my 75” Samsung.
During setup, the display kept going black and then turning back on to show the Home Screen.
i found the solution.
First, the flickering will continue through the troubleshooting process. Just be patient.
With that said, go to Settings in the Roku and then go to Display. Cycle through the different resolutions until the flickering ceases.
For my Roku model, it defaulted to the highest 4K setting. I had to drop it down a resolution setting and boom, done!
There was however a second issue too. The included HDMI cable that came included with the Roku was **bleep**. My Samsung could not consistently identify the source. So, I had to replace the HDMI with my XBOX cable for now to ensure I could at least see the Roku to begin with.
Be prepared to swap out the HDMI.
Hope this helps.
