I recently bought a Roku Ultra, and have an older HD TV, Hitachi 42 inch model LE42S605, together with a Samsung blu-ray home theater model HT-E5400. I originally had the Roku as input into the home theater, with output from the home theater to the TV. I kept getting green or black screen flashes every 3 to 5 minutes, and the TV would act as if the signal was lost and show "Detecting" on the screen for a few seconds and then the screen comes back. Audio was always there, never stopped. This happened whether or not I was streaming - even on the Roku home screen. After researching my TV and home theater, I realized I could wire it up using Audio Return Channel (ARC) and connected the Roku direct to the TV, then TV to home theater thru ARC. No problems ever since. Thought I would share the solution in case others have experienced similar and this might work for them.