(adsbygoogle = window.adsbygoogle || []).push({}); Anyway to add custom mw2 patch file without ****ing up my ps3? (jailbreaking)

Not Possible. By the way jailbreaking doesn't **** up you're system.

Can't go online I heard and I got 3.55. It seems so easy just replace patch_mp.ff but the ps3 won't allow me to do that...

data transfer .......

You can use the Iphone 3g to downgrade and jb.
but it might "brick".

Or a ipod nano 1g

if your on 3.55 there is only one way supposedly and if you think jailbreaking will eff your system up then you shouldnt attempt to do anything else you should just play the game it was meant to be played