Well, I think there is some information you are missing.
When a PKG is installed to the PS3 (among other things) it extracts all its files to a special directory. In those files is the PARAM.SFO.
So then, one can get the file from the directory (mind you, the PKG is gone, it has already been extracted), edit it, and replace it.
The problem is, you can't do this on a retail system anymore. Possibly with 1-2 games, that use online update features , that you can edit files passed to it. Games like Resistance, Warhawk and a few others worked this way, alas most do not any more.
And yes, one could in theory use any PARAM.SFO, but you should not. The SFO includes other details in regards to Audio/Video resolutions, game type (save, executable, patch), remote play etc.
Can you please relate what you have written above to the following:
Take this .PKG TITLE and then grab an edited (to FW v1.00) PARAM.SFO file (or edit your own if you wish, grabbing one such as http://download-prod.online.scea.com/medius-patch/warhawk-pubeta/warhawk/20070608_r012/NPUA80093_113_PARAM.sfo from Warhawk) and then once again using a PC hex editor such as WinHex change the TITLE ID to match the .PKG file you wish to run and save it... in this case it's NPUB30006.
Does the PKG already have to be installed on the PS3, before you can do the paramsfo editing ?? Can't this SFO editing be done before transfering the file to the PS3 ?
Also, again, how were you able to get the Resistance 2's param.sfo ?? beats me ..
Doesn't the above mean that this param.sfo editing can be done on the PC before transfering the PKG and SFO to the PS3 .. ??
According to the above, it leads me to believe that this hack can be done, while