For some time now [Tobi Friedly] has been tinkering away at porting the original Super Mario 64 from the Nintendo 64 to just about any device imaginable. One of these being the Nintendo DS, with the code and build instructions now up on GitHub, along with the demonstration video below that shows off the added multiplayer functionality.
We previously covered this project and the challenges involved. The main problem that kept him from just taking the existing Nintendo DSi port by [Hydr8gon] and running it on the original DS is that the latter doesn’t have enough RAM to load the entire game ROM into memory. The integration of NitroFS for asset streaming took some time, along with addressing sound support and overall stability. Meanwhile it appears that multiplayer support was also added along the way.
This multiplayer involves two DS systems, each running its own copy of the game. This can be nice for co-op playing of the game, as well as just for goofing around in a 120 star fully finished game with a buddy.

Nintendo hasn’t sent a cruise missile to his house yet??!!
I’m guessing either the recompilation projects are far enough in the clear to prevent them from interfering or they are waiting so they can grab all the source code and ports to use on their Switch 2+ like they do with emulators.
I don’t believe for a second that they rip emulator code. If they did, their emulators wouldn’t have problems that have long been solved by FOSS projects. (Yes, I know about them stealing ROM dumps for the Wii VC.)
Nintendo already ported Super Mario 64 to Nintendo DS and added multiplayer support.
It ported a version to be sure, but this is the full fat n64 code with multiplayer added. I don’t know if you’ve played both but Nintendo’s port feels a lot more rough around the edges than the n64 version. Porting the original code presents an opportunity to have a higher fidelity version available.
They literally already did this officially. It was a launch title.
Thanks for enlightening the world. We had absolutely no idea that they put out an inferior version that you have to use cheats/patches on just to make the controls as tolerable as the original.