iphone 4, composite cable no longer works with ios6 update

I have the iphone 4, and I used an apple composite cable to watch youtube, videos, etc on my TV through an AV input. But when I upgraded from IOS 4 to IOS 6, it no longer works. Says something along the lines of "accessory not supported" or close to that. The iphone used to go into a display mode, where nothing shows on the phone's screen, and everything shows on the TV. But now it doesn't even do anything but give me an error message. Any ideas?

In sum, it worked before, but updated, and now no longer works.