MHL

Hi,

I just got my MHL cable but I don't really understand how to switch MHL on.
When I've plugged everything in my TV detects a video source on said HDMI channel but the picture is all black. Is there anything I need to activate on the Hongmi to get the MHL to start? Do I have a version that's so old that it doesn't work? (I haven't updated it since I got it)

Thank you.