What a Wow, this brings back memories from my own Sega Mega Drive hacking days. About 35 years ago I built my own hardware development kit from scratch as a way to learn more about the hardware.
I documented the project here if anyone is curious: https://nestenius.se/hardware/how-i-built-my-own-sega-mega-d...
It's really fun to see Linux running on the Mega Drive. I never would have expected that back then.