Judging by the ear-deafening silence I'm going to go ahead and assume that there aren't any.
There are two different methods I've found to pull off cheats in-game when there were no external cheat engines present, both with some limitations:
-find the appropriate
trainer for your game and apply as you would a patch
-use the program
GABSharky (non-virused version, plz) to insert codes directly into the roms
Trainers are plentiful, however at some point they fell out of favor and they stopped being produced for some of the newer GBA games (
Fire Emblem has one, but
FE:The Sacred Stones doesn't). Also, you're pretty much at the mercy of whatever cheats the trainer's author decided to add. Most of the time they'll be the basic ones everybody asks for (infinite health, infinite money, etc.). Not that there's anything wrong with that. Once you've got your trainer file, you simply apply to your rom with IPSWin or some other patcher tool.
But when trainers fail you, you can turn to
GABSharky, a semi-useful little tool that popped up a few years ago to some... shall we say,
controversy? But never mind that, the original program works pretty good, however the author has abandoned it and it leaves a lot to be desired. The program allows you to directly insert Codebreaker codes into the rom, resulting in a permanently cheat-enabled rom file. However, it is limited to one certain code string, so you're fairly limited with what you can do with it. You also need to limit how many codes you insert, as adding too many codes will cause certain parts of the game to lag or just plain crash.
