Pokemon Fire Red cheats won't work?

Pokemon Fire Red cheats won't work?

Okay so I've recently finished the story of my Pokemon FireRed version on my GBA4iOS Emulator, and after I beat the Elite Four I decided I wanted to complete the original 151 spaces in my Pokedex too. However, there's a problem. There are around 20 different species of Pokemon I can't get without trade or cheats, and since I'm on GBA4iOS Emulator I am not able to trade. In which case I'm having to use cheat codes. I've searched the Internet however far and wide and found 0 codes that actually work for me to get Pokemon. Other codes work but not any of these. So guys can you help me? I've tried using master code and pretty much everything, but nothing is willing to work. Is there something I'm missing? Or doing wrong? Or does anyone have any codes that are certain to work for FireRed GBA4iOS? (Keep in mind that is what I'm using to play) Thanks guys!