i have a psp 1000 that used to have 5.00 m33-6 but after playing it for awhile it has turned back to 5.00 ofw. i want to hack my psp back to 5.00 m33-6. so i try to upgrade to ofw 6.35 so i can use Hellcat's recovery flasher V1.65 to install 5.00 m33-6. but when i tried to update to 6.35 ofw i get the error DRNFFFFFFCD. so i installed keycleaner v1.4 to the PSP/GAME folder of my psp. however my psp cannot run it saying that it is corrupted.

is there anything i can do to hack my psp? it really doesn't matter which cfw i use or what method i just want to play iso games and monster hunter portable 3rd again. Much help will be greatly appreciated