Undead Cheat Steps:
1. Start GameCIH and SAS
2. Start a new game
3. In GameCIH press "Input Name" and search for "undead"
4. You should get an address with the name "msDebugIsUndead". Change the value to 1 and enjoy
Edit: Seems like it works online too
Normal Health Cheat:
1. Start a game and search for 1128792064
2. Change the last adress to 4294967295 and lock
That's it ^^
Grenade Cheat Steps:
1. Do an "Input Name" search again but this time write explosion.
2. Change the value of GrenadeTimeToExplosion to 0 and there you go: Instant nade explosions