Brewology

your psp must be on a cf like 3.90m33 to use that update. for your slim you will need a pandora or some one who has one will need to help you. for more help check the tutorial section

yeh its like tbag said u need to be on CFW but when u use pandoras to downgrade and upgrade prob best not to go to 3.90m33 at the moment as it has still got sum bugs go to 3.80m33 or sumthing and just wait for a later revision of 3.90m33.

i would suggest using The Despertar Del Cementerio (a varient of pandora battery) that automatically puts 3.71m33-2 on your psp, which i personally think that 3.71m33-4 is the most stable with the most features