Its possible to do it, but you'll need a NAND backup and a hardmod to rewrite the new NAND.[...]
Partially off-topic: Has anybody tried to replace the NAND with a larger version? Would it be possible to have a 256GB NAND and install games internally? I mean there are the 8GB and the 32GB version… so the OS is kind of flexible in this regard.
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Which make me think about how does N, write the Wii U's NANDs if they need a matching CPU key before hand? I mean, they have the tools (software) to create an "unique key" for each NAND, but how dificult would be to create one using homebrew tools?
The encryption method would be the hardest part I think.