Stutter: Turn off airplane mode when using
cheats. Don't forget to delete any wifi connection if you set them to autoconnect. Or you'll go online with cfw.
Codes: Maybe before you enter the first battle to have them in the first one and turn off the "on" code and turn on the "off" code when you don't want to have the boost anymore in the next battle. If you want the boosts in every battle, leave the "on" code on and "off" code off.
To completely remove the boosts, turn off the "on" code and use the "off" code. After that, you can also disaqble the "off" code.
Think about that like, if we got an config file with boost=0, "on" code sets its value to 1, off to 0.
After it has written the number to the config file, there is no need to keep the code activated which we used to overwrite that value, because nothing else overwrite this value.
Only when you close the game, every value gets reset to default.
Using a legit Mew file with pkhex or create an unlegit mew/mewtwo with pkhex