> unfortunately anywhere with 'stong' IP laws you aren't allowed to patch anything.
I am not aware of any IP laws that prohibit patching, except for circumventing copy protection (DMCA). There are plenty of laws prohibiting distributing patches, but making and using them are not commonly prohibited AFAIK.
You can technically distribute patches, a good example of what is possible is SNES ROM hacks, where only the deltas are be distributed, and the end-user provides their own 'legal' copy; this avoids the issue of redistributing copyrighted content.
However in the EU you aren't allowed to use information obtained through "decompilation" for the purpose development/production of a substantially similar program. Which means you cannot patch any program (exception exists for the purpose of interoperability), without risking some legal liability.
I am not aware of any IP laws that prohibit patching, except for circumventing copy protection (DMCA). There are plenty of laws prohibiting distributing patches, but making and using them are not commonly prohibited AFAIK.