For Pandora ...
To downgrade (and get a custom firmware) or unbrick your PSP, u need the Pandora's Battery. There is three ways to get the Pandora Battery.
1. Find a someone who has a Custom Firmware that is willing to let you borrow their psp. You will use his psp to softmod the battery. Meaning using software to make the Pandora. If you willing to do this, follow this guide:
GUIDE
2. Hardmod the battery. Meaning that you have to open that battery up, and pulling out a pin. Note that if you pull the wrong one, your battery would be messed. If you are willing to do this, follow this guide
GUIDE
3. The most safest way, is to buy the DATEL tool battery. It is already a premade pandora battery. If so, follow this guide or use the same guide on the second step.
GUIDE
Note: You can not use Vista to run the Pandora program. If you do have Vista, plz tell me and I will give u an another guide.
after you get to 1.50 you should install the latest custom firmware you will have all the latest features and play all the newer games with no problems
to get custom firmware this will install custom firmware 3.71m33-2 then you can use the MUX 2.0 program an upgrade to 3.90m33-3
then you can go on your psp and go to network update and upgrade to 4.01m33-2 and you can go to network update to upgrade to the latest custom firmware whenever a new one is released