I don't know if all the enhancement chips were collected and decoded, as IIRC a pair of them are literally used for a single japanese-only game.
Although for IP reasons the enhancement chip firmwares can't be distributed with higan, so you have to "dump them yourself".
All the enhancement chips used in officially licensed games were collected, decapped, and dumped via an electron microscope. Yes, even the ones only used by a single Shougi game each. :)
I still can't get over the tragedy of what happened to them. That shouldn't have happened under any circumstance.
from https://eu.usatoday.com/story/tech/2021/07/23/how-toxic-onli...
That's hard enough for me to think it's legit, though I'd agree that it's not conclusive.
I'm also close to finishing N64 and maybe halfway there for NES (which I have no illusions on completing ever).