i have put a custom firmware on my old phat ps3 at 3.55, but i dont know much about downgrading from higher firmware. my cousin just got a slim with 3.70 on it , i used MinVerChk and it said it can be downgrade all the back to like 2.55, of course i just need to get it back to 3.55 so i can put a custom firmware on it. so guys what are my options here ? whats the best way to downgrade this ? assuming it can be?