I have a LG 4K tv, LG SH4 sound bar and a Roku premier plus. Currently I have the Roku connected to the Soundbar via HDMI and he sound bar connected to the TV via HDMI ARC. I cannot get a 4K display with this set up. When I connect the Roku to its own HDMI port and the sound bar via the ARC port I sometimes get sound through the soundbar and 4K HDCP 2.2 from the Roku and TV. However when I turn the tv and soundbar off this connection is forgotten everything needs to be reset to sometimes get it to work. Any suggestions to get a constant connection? Thanks.