Hiya tzirf, I recently came across your plethora of fix material after largely having given up hope of fixing my belived wiiu.
A few years ago i hacked my black 32gb wiiu i got with Mario 3D World and NintendoLand pre-installed.
The details are somewhat hazy at this point since it's been a bit, but basically something was downloading and installing itself (or fixing itself), and i got one of the error messages, and rebooted and everything was just black. there was just now audio/video anymore.
I tried some methods Id read about on gbatemps and through some vids Id watched like using a pico to boot into a diagnostic recovery program to confirm it was the nand, but I dunno if I dont have the skill to do it or what but I haven't been able to get past the black screen.
I purchases a nand-aid, but after researching the process of installing it, I dont have the tools or skills to do something of that caliber and I don't want to risk trying to bring my wiiu to a local gadget repair bc it has great sentimental value to me personally (my grandmother passed away and we were very close, and after i arranged the funeral and had settled everything i bought the wiiu to help me with the pull myself out of my grief.)
So Im posting here in the hopes that somehow someway I can fix my beloved wiiu.
Thanks in advance.