check this out... http://savemii.net/troubleshooting.html#C if your firmware is below 3.3 you can used the original Mario kart game to update. http://www.youtube.com/watch?v=YaCDUb3n--Q&feature=related
Uh, no. Mario kart doesnt contain 3.3 so you cant unbrick with it unless you're on 3.1 or lower. Wii fit or animal crossing both has 3.3 so you could use either of them. And I've heard that the new sonic the hedgehog game has 3.4 but I have zero interest in playing it so I don't know if it's true or not.