How do you enter cheat codes on mercenaries2?

You need.the patch from xbox live,and you of course need xbox live,if you do this is what you do. First,hit back your PDA(back button),TYPE in:LB RB RB LB RB LB LB RB RB RB LB. Hit back again you will get a promt READ CAREFULLY! Go back to you PDA don't move anything all you need is the d-pad