Hello,
I just got a new Vizio M Series TV (MG507-G1) connected to a Roku Premiere+ (4630x) in the ARC HDMI port. The TV will power on and switch channels when any button is used on the Roku Remote (RC-GR3) but not the volume controls. I have CEC enabled on the TV and it shows up in the CEC menu. I have one touch enabled on the Roku. I have done a factory reset on the TV but not on the Roku yet. I have checked for updates on both.
Any help appreciated.