upgrade to 2.80:
https://www.digitalworldz.co.uk/index.php?resources/1795/
downgrade to 1.50 :
https://www.digitalworldz.co.uk/index.php?resources/1597/
upgrade to custom firmware 3.52 M33 :
https://www.digitalworldz.co.uk/index.php?resources/1659/
then do the # patch (3.52 M33-4)
https://www.digitalworldz.co.uk/index.php?resources/1826/
make sure your battery is 75% + charged.
format your memory stick before you start and between each process.
to upgrade to 2.80 (first link) connect your psp to pc via the USB cable and goto the PSP\GAME folder and make a new folder inside called UPDATE in capitals and put the 2.80 sony update EBOOT.PBP in the UPDATE folder.
then run the update from the game menu / memory stick on the PSP.
read the "read me" files included in the 2.80 downgrader and the 3.52 M33 installer. they will explain what you have to do
aaaaagggghhhhh just noticed you havent got enough posts to access the download section.
new links ( replace the ** with tt )
2.80 update and 2.80 downgrader : h**p://www.calo-hacks.com/2.80downgrader.html
the sony 2.80 update from here is an easy installer i think so just follow the read me files.
3.52 M33 installer and #4 patch : h**p://www.calo-hacks.com/3.52m33.html
dont forget you will need the 3.52 M33 installer for 1.5
"""Upgrade from firmware 1.50 Full Installation Installer """