http://dl.qj.net/dl.php?fid=14678 - use this for 3.71 rename "UPDATE" to "RECOVERY", access usb via recovery menu and put it in "GAME", download the original 1.50 firmware, rename it to UPDATE.pbp and put it into the recovery folder then select "run program at PSP\GAME\RECOVERY" This will take you to 1.50
This will only work on 3.71 custom firmware. You'll need an original firmware 1.50 file to make it run, this isn't supplied in the file download.
If you go to
www.dark-alex.org there is also despertar_cementerio, this will allow you to make a pandora still but it will take you straight to 3.80M33-5, you will have to download the other files neccasary to do so, but it will save you going all the way back to 1.50 and going through the whole process again. Obviously if you use this, the above is not applicable.
I hope this helps you, good luck
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