I was the first MSX generation, but I was using NEC's PC-6001, so I wasn't interested in MSX. The same goes for Famicom. Exactly around 1980-82.
@Stephen and @Drake at SMC were specialists in Gameboy and other game consoles, so I learned a lot from them and there are more things I want to try myself...
Today is the MSX that I'm personally interested in. Actually, there is not much of a boom in Japan. Buyee buys most of the items on Yahoo Auctions.
I hear there is quite a boom in Europe.

I designed this card in one day because I ran out of RAM when loading cassettes. *The schematic is not my original
still in the testing stage...

Now that I have the card edge footprint, I designed a ROM card that uses an EPROM flashed with a ROM programmer using something like a 27C128. It was over in a matter of hours even faster.

This can switch the EPROM to be mounted with a jumper pin.

It's possible that it won't work the first time, but if it goes well, I think I'll open source the non-SMC version.