i want upgrade from 5.50GEN D-3 prome 4 to 6.20TN-C to play final fantasy dissidia 012..my psp model is psp 2000..i saw some post saying cannot upgrade to OFW FROM CFW...CAN ANYONE HELP ME OUT?

if i run dissiadia from 5.50GEN D3 PROME 4 the game can start but hangs before i get to play...the scene at the begining where the cute 'creature' dunno what name finish talking and start loading..psp restarts..help...doing for 10 hours alr..no solution till now..
HELP!