The “almost” was due to some special chips present in some Super Nintendo cartridges. The SD2SNES has already implemented several of them, including DSP-1, CX4 and ST010. But I got the Super FX and the SA1, that were used in classics like Star Fox, Super Mario World 2: Yoshi's Island and Super Mario RPG: Legend of the Seven Stars.
Until then, It was believed that the hardware of the SD2SNES not even bear the Super FX and the SA1. But a few months ago the situation started to change, a guy whose nickname is redguy emerged in the forums of Krikzz site announcing that he was implementing the Super FX. Their implementations are not yet on the official firmware, but can be downloaded on Github of redguy.
In April I made a live testing various Super Nintendo Games that use the Super FX, including the Star Fox 2, accompanying the Super Nintendo Classic Edition, and that finally can be played on real hardware without requiring cannibalizing other cartridges that use the Super FX. Check out the files that live:
And the new surprise is that the redguy now is implementing the SA1. Is the best use I can imagine for that line “And not knowing it was impossible, He was there and did.”. Still no firmware available with the implementation, but a video posted on Youtube already shows the Super Mario RPG: Legend of the Seven Stars running… and very well!
Now is to wait for the release to the public. And imagine: What will be the next big thing that will bring us still RedGuy?