hello i currently have my xbox hooked up with the HD inputs and i could play splitscreen
try this out its what i did
on xbox dashboard have profile 1 signed in then sign in profile 2 on controller 2
choose either new world or an existing one
when in game it should pop up saying for player 2 to press start to join
Thats great you got it to work for people but I'm really quite surprised that some people are not using HDMI cables, the price of HDready tv's has really plummeted over the last year and the different in quality is worth every penny imo!