I had some issues hacking my friends PSP, so I did some snooping and found a program called PSP Grader v0.2 from the makers of Pandora GUI. With this program, you can easily write Pandora files to your PSP... you just need a Jigkick at hand.
NOTE: I or the creators of this program, X-Projects.com, take no responsiblity for any damage this may cause to your psp, use at your own risk.
Microsoft .NET Framework V2 capable OS
A PSP (duh)
A Phat Battery
I've personally only tested this on a phat myself, but you can try it. The official guide says it will work with slims as well, so I don't predict you'll have any problems.
1.) Download PSP Grader v0.2
2.)Download 1.50 eBoot
Download 3.90 eBoot
3.)Start the Program
4.)Insert and begin the USB connection
5.)The program will automatically detect your PSP drive
6.)Click start when ready, it will format your memory stick and copy the required files to hack your psp onto your psp
WARNING!: Back up your precious files (music,photos, etc) to your computer, for formatting will completly erase all of the content on your memory stick
7.)Wait until it says "Preparation Complete"
8.)Safely turn off your psp
9.)Make sure your MMS is inserted and insert your pandora* while holding down the L-trigger
10.)Wait a few seconds for the MS LCD light to come on, and the CFW installation menu to come up
11.) Press x to install 3.90 M33-3
12.)Congrats! You just hacked your psp!
*If you need to make a pandora, go onto Youtube and learn how to softmod your battery or get your friend with a CFW to make your PSP battery a jigkick.
Or, if you have $20, buy a PSP Battery Service TOOL
This simple device is cheaper then a TOOL and is much more worth the money. You just insert your battery into the device, and with the click of a button, you can change your battery into a Pandora back to a normal battery or vice versa. This simple proccess takes under a second! Plus, it works with phat and slim batteries! So if you bought the TOOL battery from phat but you bought a slim you want to hack, you have to buy a whole new TOOL battery!
Program Credits go to X-Projects.com