HackMii Installer v0.5
its suppose to be a bit buggy though but here it is!
If you updated to v4.2:
■BootMii/boot2 was wiped only if your boot2 version was v2 or v3. Just reinstall it.
■BootMii/IOS will still be there.
■DVDX got deleted, reinstall it.
General advice: Donít use some random update application, just update through the system menu if you really want to update.
General note: If you install anything with this installer version, update all the components you have already installed. E.g.: BootMii required some changes too, so the HBC with the new title ID gets loaded.
Note about DVDX enabled applications: Because of the new title ID, all current applications will fail to load DVDX. libogc needs additional code that checks for the new title ID. All DVDX enabled apps need to be recompiled afterwards.
That link is for the Cat in the box hack...Hmmmm