Earlier quoted context omitted.
I don't think people on HN understand what a derivative work is, considering how often I see it referenced incorrectly. You can't make a derivative work without a license. That's why it's derivative. It derivates from the copyrighted work and is therefore within the domain of the copyright and under the control of the copyright's owner. A Harry Potter spin-off about Hermione (I don't know anything about HP, sorry in…
If the patch is distributed on its own, without the original binary, is it still a derivative work? Is the unique, creative work of writing "perform XYZ instruction at XYZ address," in lieu of the original executable, still derivative? This is actually an unanswered/unproven question that comes up quite a bit in automotive tuning, where individuals and tuning companies modify OEM calibrations and create application s…
GCC made an enhancement board for Missile Command and later for Pac Man ("Crazy Otto", which became "Ms. Pac Man"). Rather than employing simple "ROM hacks" as other enhancement board manufacturers did, GCC specifically built their enhancement hardware not to contain any code copied from the original game ROM. Their hardware patched the existing ROM only by overlaying their code onto the original ROMs, not by copying any of the original code[1].
There's some neat detail in the background slides here[2]. I'd love to hear that talk but I'm not immediately a recording of it.
[0] https://en.wikipedia.org/wiki/General_Computer_Corporation
[1] https://web.stanford.edu/class/sts145/Notes/3_game_business/...