My 4.2U got bricked after downgrading to 3.3U and then installing a 4.2U theme. i purchased a triwing screwdriver and opened up my ngc pad, i managed to get to the recovery savemii menu thing (displays the installed firmware) so i inserted madworld and after a few seconds the 3.3U on the bottom right of the screen goes away and all i'm left with is a black screen. i let it sit for 10mins but nothing really happens.