huh, just so everyone knows I sent my WiiU in for repairs a couple weeks ago when it was having problems. I had installed the homebrew channel on my vWii, and made sure to delete any and all traces of it that I could before sending it off (I had not tampered with any IOS stuff to avoid any issues like the above picture)
I got my WiiU back, the pcb board had broke, and no mention of the homebrew channel ever existing on there was included with the paperwork I received.
If the error was due to messing with files that most the internet tells you to avoid, I'm sure I would have received this letter. Just be careful, I'd avoid changing any IOS stuff on the WiiU even if it's "safe and vWii specific" versions since that's the sort of thing that can brick the console if one were to goof, resulting in a sad letter like this one.