You might ask: “Why 6.60 and not 6.61?” The answer is . While 6.61 is newer, 99.9% of homebrew, plugins, and cheats are developed for 6.60 . PRO-C2 for 6.61 exists, but many tools (including Chronoswitch and some version spoofers) work better on 6.60. Unless you need to play a specific game that requires 6.61 (extremely rare), stick with 6.60.
If you have a PSP 1000 or an early PSP 2000 (TA-085v1 motherboard), you technically have a "Pandora Battery" capable motherboard. However, software updates are safer now. psp 352 m33 upgrade to 660
On your Memory Stick, create the folder path: PSP/GAME/UPDATE/ . Place the EBOOT.PBP inside the UPDATE folder. You might ask: “Why 6
If the update fails with an error or claims your version is "9.90," follow these fixes: Version Spoof Fix Unless you need to play a specific game that requires 6
There is no such thing as "PSP 352 m33" – you likely mean 3.52 M33 (a very old custom firmware). The process below works from 3.52 M33 or higher (including 5.00 M33, 5.50 GEN, etc.) to 6.60 PRO-C.