Trainer Help for MW3 version 1.5.388 Single Player

Yes there is an anti-debugger too in the Single-Player mode of MW3 in latest patch 1.5.388

I'm trying to do a trainer and i'm working on the NoRecoil cheat.

Here's the addresses to NOP.

0x004FFD1
0x004FFD2

NOPping those make the gun have no recoil and does not make the game crash during loadings.

Now here's the problem...When I NOP those, the game doesn't crash immediately. It freezes until you click back into the game. Once you do, then the game crashes. Protecting itself, I guess... Is there a way to modify those 2 addresses without making the game to crash?

I know it does work because I kept a backup of both EXE of MP and SP of version 1.5.387. The pattern was similar and when I nop the addresses, the gun had no recoil and no game crashes. Please help me.