This is the newest OFW (official firmware) from Sony for the PSP. It completely wipes out any trace of hacks. But this OFW is needed (I think) for the new PSN and PS Store.
Visit this link for instructions on installing and downloading it.
http://uk.playstation.com/psp/support/system-software/detail/item375212/Update-features-%28ver-6-39%29/
Hope this helps.