Better not to spoil the fun and thrill of the game like Biohazard 4 by using cheat.
Be a man and finish it by your own or otherwise you can use walkthrough of the game for getting the idea's how to defeat the boss.
Yeah cheat codes ruin the fun... especially in single player games... now if you are playing against someone else or multiplayer cheat codes rock because you can pawn your opponents... but yeah still unfair... but fun unfair