Flashing solved had HDMI cable next to electrical power cord
I've lived with this problem for 2 years. The HDMI line goes 16' feet from home theater to projector I had the line on the electrical line that went to projector about 2 years ago i had fleshes and disconnection had to always go into settings on Home Theater (HT) whenever it would start flashing it would knock it off signal. I had the HDMI cable placed with the power cord that went to the Projector I decided to separate the lines from being next to each other and wow the flashing quit the disconnecting from HT is now functioning normally. After 2 years of this replacing ROKU stick 3 times the problem is totally solved. I'd switch Roku units the problem went away was always blaming ROKU.