I followed your thread regarding vwii in your wii u. I have similar problem where my WII U (PAL) ver 4.0is stucked in SSMB (custom stage) when im trying to hack.
I already check my files and all are europe file to hack. Im using micro sd card in sd adapter. is this a problem? Could anyone help me? I already tried many times (10 times) and it always stuck in stage builder.
What i already did
-check everything is eu file (hopefully im correct)
-follow all the instructions (e.g. delete all save files including default custom stage, save files, put SD memory once in SSMB)