Another EASY way to fix corruptions:
Some versions of DevHook has caused minor corruptions. Also the new gpSP GBA EMU by Exophase can cause the config file to get corrupted sometimes when trying to load a game that caused the EMU to crash.
A simple and quick fix to memory stick corruption is as follows:
1. Connect your PSP to PC via USB connection.
2. Open the command prompt
3. Type CHKDSK E: /f
E: is just the drive letter that the PSP shows on my PC. It may show as I: or H: or another letter. If that is the case just substitute E: for the correct drive letter.
This simple and quick command will fix any and all corruptions on your memory stick.
Enjoy!