I think i found something!
I have a Us Psp 1.5
Well i got my Advent children umd in today. All day long I have tried to get this umd video to play but no luck. Well i started thinking... The problem is when i change the region its not going to play sence it needs 2.0. What if i changed the region then tried to update to 2.0. I did but when i got the 2.0 to start it just show the update icon and the x and o at the bottom. You couldnt go past anything but you could get out and it would restart your psp if you did O left O. I did this and went back... Now my us Psp 1.5 is acting like a Jap Psp 1.5 when i pop in the advent children umd it says " Disc could not be read." but when i pop in my other us umd's they say there the wrong region code. I have restarted my psp a few times still does the same thing.. The only way i can get it to read my other umd is if i go into umdemulator and change it. Then if i go back in and hit triangle to go back to regular setings its still acting like a region 2.
Now alot of you are going to say well you can use wab changer and trick the umd movie to work...uhhhh.. No it doesnt work like that Umd music and umd movies that need 1.52 or 2.0 need it for a reason for some code so it wont boot if you change the region... But doing it this way maybe i can update to 2.0 and have it stay as region 2 so i can watch my movie...