use bannerbomb to run HackMii Installer and install HBC. The latest HackMii Installer installs a HBC which works on 4.2.
If you have cIOScorp, the Installer wont work. Remove cIOScorp, and do yourself a favour - leave it off. Its crap and messes up your wii. If you dont have cIOScorp, the Installer will probably still fail cause you Waninkoko updated, and he thought it would be a great idea to patch EVERY IOS, and Team Twiizers disagree, because patched IOS are possibly unstable, and also they dont have time to add support for every IOS patch, so you'll need to install unpatched IOS34 and IOS61. You can repatch IOS34 after if you really want, but I'd advise against it.