We got an incredible deal on a Vizio M series but have been unable to get 4k content to work. 1080p yes 4k no. The onboard youtube app wont render 4k, and the samsung 8500 blu ray only plays 4k discs in 1080p. I've tried different 4k hdmi cables, tried different Hdmi inputs, I've tried bypassing the amp and running the HDMI directly to the tv, and nothing seems to work. I'm hopeful that it's simply some setting that I'm missing. Thanks for any light you may be able to shine on my situation. Thanks in advance.