WHAT YOU NEED:
(A) 1 or 2GB SD card FAT32 formatted
(B) boot.elf from hackmii_installer_v1.2 in the root of your SD Card
(C) Smash stack hack files on your SD
(D) MMM in your \apps\ folder
(E) IOS236 Installer MOD v6 Special vWii Edition (v2, w/ latest HW_AHBPROT patches) folder in your \apps\ directory
(F) IOS36-64-v3864.WAD file in your SD root (hint: google ‘sendspace kl6o78′ and download the sendspace file)
(G) Your other desired *.WAD (games, emus) in \WAD\ on your SD CARD
* IMPORTANT: Do NOT insert your SD card before STEP #3 below *
WHAT TO DO:
#1 Power on your Wii U, insert SSBB disc and launch Wii Mode.
#2 Once in Wii mode launch the Wii Disc Channel
#3 When the health warnings appear, insert your SD card
#4 Navigate in the menu to VAULT, and select STAGE BUILDER.
#5 Follow the instructions on screen and select INSTALL HOMEBREW CHANNEL.
#6 Launch IOS236 Installer MOD v6 Special vWii Edition from HBC
#7 Launch MMM, press the LEFT direction once on the DPAD, and then navigate to “236″ and press A.
#8 Install your favorite WADs
credit: bubba (WiiUHax.com) (big thanks for walking me through all the steps!), damysteryman (modified IOS236 installer for use on Wii U vWii)
UPDATE: Added link to v2 IOS 236 Installer MOD w/ latest HW_AHBPROT patches