Same issue on PSP-1000, OFW or CFW. Even in the middle of running a Magic Memory Stick software (e.g., Despertar Del Cementario) it is susceptible to the freeze/crash/shutdown (making it difficult to unbrick--I have to put in the Pandora battery ~10 times until I get through the entire unbricking process without a crash). I fixed keys with Key Cleaner and reset ID Storage. Also fixed MAC address. Formatted FLASH partitions multiple times. Found there were 5 bad blocks and used some NAND Storage tool to try to format around them or something. None worked. It has to be hardware related in my opinion. If any PSP hardware genius out there has an idea where to look to resolve, it might be helpful to post