I have power cycled this device. I power cycled my TV. I have power cycled my stereo. I've connected directly from my Roku into my stereo, or from the Roku directly to the TV. I have tried about six different HDMI cables. The Roku is flickering on my television screen, regardless of which television I connected to. Both my PlayStation and my Xbox don't flicker on the TV when connected through the stereo or directly to the TV.
I have even tried blowing on the Roku Express like we used to do with the Nintendo cartridges...kidding.
The screen flicker could be described as follows. Roughly once every second there is a flicker or jitter on the left half of the screen only. I can't adjust the refresh rate on my TV or on the Roku Express. I have a feeling it has to do with the refresh rate but not entirely positive.