I bought New Super Mario Bros Wii a couple of weeks ago (great game by the way) and with the disc inserted, a message appeared on the disc channel telling him I had to install a small update. I did so and nothing "wrong" happened. I can play the game, and I still have System Menu 4.1U (I don't plan to "upgrade" to 4.2.)
Problem is? Bootmii no longer appears when turning the Wii on. Has it been deleted? Has anyone had this problem already?