Personally, i do not know about emerald, BUT, I did with mu LeafGreen, and got like 99 masterballs from my brother's friend's replay.
action replay
You cant you only get one ( without action replay )
its 5484533593x ;) trust me it works
$#@! no
In Pokemon marts if you have the action replay or what ever it is for game boy
Infinate master balls in pc: c674b60f b309f994
you need a cheating device e.g. action replay = ) or clone on emerald (and migrate)
Give your Master Ball to a Pokemon to hold, then clone it in Emerald with the cloning glitch.
Use action replay. Note: Dont use it
You have to use and Action Replay which can be purchased at most video game stores.
action replay no other way to bad hahahahahahaNo, a game shark you IDIOT!!!!!!!!!
with action replay you can get 999 master balls