Yeah the WiiU vc inject forwarder. I *think* I have the correct naming. sd:/apps/nintendont/boot.dol
Downloaded the lastest loader.dol from github (renamed it to boot.dol). Deleted all the other files on /apps/nintendont after it didn't boot as well (meta.xml and icon.png namely).
I read that if you boot up vWii mode, exit it from it, then launch Haxchi and then the Forwarder, it'll work. I tried that and it does work, but it's way too cumbersome. The poster suggested that a Wiiu VC injected homebrew channel was an ok compromise since you could boot nintendon't using the gamepad, but sadly he removed the link to it.
it's a bit frustrating...
Do you have any USB devices plugged in? Try removing them all. You can also try adding an HID device. Someone here claimed adding an HID device resolved their black screen issue.