Some people have done this, but you need to transplant at least the CPU from an original. Those chips weren’t built for anyone else. https://www.reddit.com/r/Gameboy/s/FEAH2VhBRT
There is a variation on the new-pcb and components approach called the "Ultra Boy Colour" which doesn't require any parts from an OEM Game Boy Color.
It can use a clone CPU that was manufactured (until recently?) for the "GBBoy Colour" (and could also be pulled from the sort of failed SGB-like clone called the "Extension Converter for GB").
> I redesigned the Gameboy Color from the ground up
> based on the premise that it wouldn't require any
> components to be harvested from a real GBC, so it
> would be compatible with both the original GBC and
> clone hardware taken from a GB Boy Colour- since
> the KF2007 clone CPU from the GBBC is practically
> a drop-in replacement for the CGB CPU found in a
> real GBC- no software compatibility issues at all.
It can use a clone CPU that was manufactured (until recently?) for the "GBBoy Colour" (and could also be pulled from the sort of failed SGB-like clone called the "Extension Converter for GB").
https://www.reddit.com/r/Gameboy/comments/w0wrt5/no_this_isn...