This is for TU 26 http://minecraft.gamepedia.com/Console_Edition_version_history#xbox-TU26
I was testing out the new custom superflat feature when the game froze, I tried again and found out it was when you click yes.
How to get to this scene:
1-Get onto minecraft Xbox360(I only tested it on this)
2- Go into create a world
3- Set it to a superflat world
4- Hit customize superflat
5-Hit A while hovering over a layer.
6- Change the layer however you want to(height and/or block)
7- Hit save- Here is where it freezes.
8- Well hit that button on your console to restart it!