My Roku Ultra would display a blank blue screen when I had my HDMI cable connected to the 2.2 HDCP ARC "In" port of my Onkyo TX-NR838 AVR. The HDMI cable "Out" was connected to my Sony 4K TV eARC "In" port. (Roku audio and video would display properly in 1080p resolution when connected to a non 2.2 HDCP port on the Onkyo AVR.) THE PROBLEM WAS WITH THE SONY TV HDMI SETTING. Fix: Go to Sony TV Settings - Channel and Inputs - External Inputs - HDMI Signal Format- HDMI 3 "select" Enhanced Format/Dolby Vision. Once selected ROKU audio worked perfectly, displaying video in 4K. (The Sony HDMI signal format was set at "Enhanced", which caused Roku to NOT work).