If your on system menu 4.2 and no longer have vulnerable IOS you need to use bannerbomb to run DOPIOS MOD running on IOS 250 to install a clean IOS, IOS 36 shuold be fine that will allow the main hackmii installer to run. If bannerbomb isnt working you have either a the wrong version or b running from wrong location. Get the hack 4.2 pack from ZXZeros guide if on 4.2 for a working version of bannerbomb, if your on 3.x get the update to 4.2 pack from zxzeros guide and use that version of banner bomb, both require running from a different place, but you will need them to run DOP IOS MOD to reinstall a vulnerable IOS, if on 3.2 you might want to install a clean IOS 34 as it isnt used by anything.