411 REFERENCE · Wikibooks
PSP/Remove GEN Version Protect
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
Open VSH menu by clicking on the Select button from xmb(main psp menu)
Change USB device to Flash0
Connect your psp to pc
Navigate to \vsh\etc\
Open version.txt using notepad or wordpad
In the first line change the 9.90 to 5.50 and save.
Disconnect your psp from the pc and change the USB device back to Memory stick in vsh menu