There are a few things in your post that put up a red flag. For one, you say you have a NTSC-U console. Why would you be going off a guide thats for pal systems? 2. If you went and downgraded to 3.2U, why would you let NSMB upgrade you again? That made your downgrade pointless. Also, was the game the same region as your firmware AFTER you downgraded? If the game region was different than your firmware region, then you bricked your console.