I recently got an old fat PSP-1001 for cheap and was inclined to softmodding it. When I got it, the bottom of the PSP's browswer menu says 'M33 Custom Firmware' while the system information says it is 'Version 5.55'. I wanted to update this firmware to 6.20 and install a new cfw, so I tried using Hellcat's Flasher 1.65, and everytime I try using it it says the program is corrupted. Additionally, I can't run the PSP in recovery mode on start-up, which I've read you can do with PSPs with a cfw. I've looked around and can't find much info besides perhaps a Pandora battery. Basically, what is the problem with this PSP and can I remove the old cfw to install a new one or what? Any help would be appreciated.