5.00m33 update goes in PSP/GAME/UPDATE with 500.PBP in the same UPDATE folder and a second 5.00.PBP at the root of the PSP memory stick ,
it should upgrade from 3.71m33 to 5.00m33 just did it on phat psp ,and since sony's 5.02 it wont connect to Playstation store it say update to latest update ,is a 5.00m33-4 required or is it PSP settings, got it to connect to Playstation Store on 5.00M33-3 just reinstalled the update again.