10th color code?

[Steveinator]

Does anyone know how to unlock the 10th color? According to the developers, it can only be unlocked by inputting a certain code in a certain screen.

Some people are reporting that inputting "Down -> RB -> Up -> LB -> Y -> B" on the "controller select" screen for a local vs match is supposed to do it. However, I've been trying it over and over again and it won't unlock for me. I can't tell if they're lying or if I'm doing something wrong.

EDIT: I found out what I was doing wrong, I took too long to start inputting the code when reaching the screen. A banner popped up saying a new color was unlocked.