TLDR; vWii plays all GC games fine. Wii plays all games except Melee just fine. I'm using the same USB drive: same isos, and same nintendont files. Everything's up-to-date. How can I get Melee to work on Wii?
I have Homebrew installed on both my Wii U and Wii. I can play Melee on my Wii U...