How to activate a cheat in a iPhone pokemon crystal?

When I put in 910504D2 the pokemob I want didn't come out please help

Hard to say since your trying to hacked a hacked game.

That's a wild Pokemon modifier - you use it by enabling it, and initiating a wild Pokemon encounter by running into some tall grass or something.

Here is the first set of codes for Crystal from GameFAQs:

http://db.gamefaqs.com/portable/gbcolor/file/pokemon_crystal_gameshark.txt

Here is Psypokes' collection:

http://www.psypokes.com/gsc/cgameshark.php

Here is Supercheats':

http://www.supercheats.com/gameboy/pokemoncrystalcodes.htm

Here is Pokezam's:

http://www.pokezam.com/games/gameboy/crystal/gameshark.php

Here is PokeDream's:

http://pokedream.com/games/crystal/gameshark.php