IPhone 4 HDMI adapter won't work?

I have an iPhone 4 adapter like the one above to display video on my TV. When I tried using it however, all i got was a black screen. When I unplugged the adapter and plugged in my laptop to its HDMI port, it worked. I never changed components and it was always on HDMI 2 which was the port it was connected to into The TV. Any suggestions?
IPhone 4 HDMI adapter won t work

Connect the 2 devices while both are powered off… Turn on the phone first. Then the tv… They should make the edid handshake and work properly.also. You may have to activate the video out on the phone. You may have to google it.cheers