I have one of those yaroze things. I had all sorts of plans for it. Until I realized that the memory on the thing was identical to the size of the normal in store ones and getting at the CD for extra storage was basically broken at the SDK level. That made debugging 'interesting'. Even splurged for the codewarrior dev kit. It was a decent step down in tooling and memory that I could get on other platforms. Kind of fun for a bit.

Same. As far as I know, though, the black PS1 didn't actually do anything special to enable development, it just allowed Sony to arbitrarily make the devkit incompatible with retail PS1 consoles. It still required a special memory card dongle and boot disc in addition to the special console model for some reason. I seem to recall that someone cracked the boot disc to run on retail consoles without the dongle, and the serial link just needed a level shifter like a MAX232 (though these days you'd probably use a USB UART like CP2102 or FT231).

I too remember being mesmerized by the image of the black PS1 “developer” kit.

It truly captured my imagination and alongside the movie Hackers from 1995 is probably one of the reasons I ended up wanting to be associated with computers in my future as a child.

Go on, challenge yourself. Learn C. You'll become a better developer from broadening your horizons

yaroze devkit costs upwards of $10,000 USD now