You will probably need an MHL adapter. With this I can download from Mediacom TiVo or Netflix to my old cell phone (via wifi) and connect to my TV's HDMI port in my motor home and watch shows I have recorded.
Here is the catch...the newest cell phones have eliminated from their internal system the MHL necessary for this to work. That is probably why you can not get audio when you simply hook up the HDMI to your phone.
You must have the MHL to HDMI converter and your phone (or device) must contain the MHL programming.
I use my old android phone (Note) which works perfectly. Netflix does have a limit on how many it will allow you to download to your device at a time, but I have never found that to be a problem. I just delete after I've watched them and the next time I am near WiFi I download some more.
I love the system. I do not have satellite so this allows me to watch my favorite Netflix shows even when boon docking in an area with zero TV reception.
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