The standard EDID on a 3G Just Add Power Transmitter does not currently display a 4K Roku at it's native resolution settings. To get a Roku to output 4K video, a special EDID must be applied.
If you are experiencing video tearing on 4K60 content on the Roku, follow the steps below to optimizes video encoding for Roku 4K60, as default settings do not always provide ideal performance.
astparam s ast_video_quality_mode 3;astparam save;reboot