There is new version of old exploit ...
What's new?
Now you don't need WiFi connection and CFW PSP.
It also take much less time to run.
Download here: http://zdoom.ic.cz/psp/moh-exploit-v2.zip
Mirror by n00b81: http://upsp.ws/moh-exploit-v2.zip
... and read info.txt ...
Tested on PSP-1000 with official FW 5.51, again thanks to PSPdemon for testing.