One of the things I'd always wanted to do with my Wii U was to mod it. I even bought the ds games that were supposed to help with breaking open the os before they shut down the store. I just never got around to it.
Things have changed drastically since then and I think this might be even easier now with way more to do including getting the wii u online services running again.

I'm just waiting on a power cable to see if that's what the problem with my wii u is. The cable I have seems to have some fraying on it so I'm hoping a simple replacement will get the thing working again.

This is pretty cool. Someone cut up the wii's Gamecube mobo to its bare minimum to function correctly, added 2 or 3 microboard and housed it in an adorable mini gamecube case.

I have a GC and would be very willing to get a micro console like this. I've been thinking about modding my current gamecube to red sd cards instead of discs since the optical drive will eventually die.

This channel deals with retro console mods. It's done pretty well and can has given step by step instructions for different mods.