Team Twiizers have released an updated HackMii Installer for the WiiMode on the WiiU, using a new IOS exploit and HBC title ID.
Source: http://hackmii.com/2012/12/hbc-release-for-a-new-wii-u/
Source: http://hackmii.com/2012/12/hbc-release-for-a-new-wii-u/