if you have a hacked PS3 there should be a version spoofer
but they can be a litter tricky to use and may make thing go bad latter if you forget to remove them when updating CFW or downgrading
so just be careful
A GAME UPDATE IS NOT A FW UPDATE
just keep the ps3 disconnect for the Internet and you should be fine
BUT newer game may have a FW update on the Disc so be careful
newer game do work on 3.55 CFW with extra fixes
the BEST thing to did is have 2 ps3
one Hacked (and no Internet)
and a
2nd for Official FW
like many 360 owners, that have a Flashed 360 do