[Wowfunhappy]

For what it's worth, Wikipedia says that some official N64 games did use custom microcode: https://en.wikipedia.org/wiki/Nintendo_64#Graphics

> Nintendo 64 games running on custom microcode benefit from much higher polygon counts and more advanced lighting, animation, physics, and AI routines than its competition. Conker's Bad Fur Day is arguably the pinnacle of its generation combining multicolored real-time lighting that illuminates each area to real-time shadowing, and detailed texturing replete with a full in-game facial animation system.

[xgkickt]

Probably more accurate to say the custom microcode tools were not given to third party developers. From what I remember, you had to list the microcode used on your submission form, and Nintendo checked for it in your ROM. Did some third parties make custom microcode? Highly probable, but I do not know how many were able to ship with it.

[tadfisher]

Factor 5 famously customized microcode in essentially all of their N64 games. According to some emulator devs, the F3DEX source was available in the SDK and intended to be customized [1], so it's interesting to hear a different account .

1: https://github.com/gonetz/GLideN64/wiki/The-masterpiece-grap...

[xgkickt]

Interesting. I was on PlayStation so I only heard about N64 dev at lunch. Factor5 were much closer to Nintendo than we were, and also known to be a bit good. Plus SDKs change over time. Take PS1 for example. We didn’t get GTE register details and inline functions initially, just libraries, and the more open it became the more we wrote in assembly.

[Wowfunhappy]

Huh. Well, Conker's Bad Fur Day wasn't first party, but I guess Rare probably got special treatment?

[xgkickt]

Yes, 2nd party privileges.

[486sx33]

Rare got all kinds of privileges, heck they developed their own unofficial dev kit. https://www.behindthecode.ca/rareware-n64dev/