Good news, there is a downgrader for 2.80, which was realesed in late december. Firset, i need you to open your UMD drive at the back where you put in disks, which btw when you downgrade you can just download the games..... So open it up, and tell me if you see ICI3001
If you are not like that, then you can downgrade with this
http://pspupdates.qj.net/2-80-Easy-downdater-down...er/pg/49/aid/77195 easy downgrader