>>52874405IIRC, the differences in Pokemon data structure result in NEEDING a "buffer" to present the GB/C data to the GBA games as legible Pokemon, and there's some firmware awkwardness in cross-applying the Link Cable protocols.
The two realistic options are a GBA-N64 connector or the GBA-GameCube connector being compatible with the GB/C link cable protocol, to wash it through Stadium or Colosseum. Less realistically, e-reader or gameshark data injection shenanigans may be able to jailbreak the GBA in the required fashions.
>>52877213By physically cutting apart the two different Link Cables to wire them to a modern microcomputer converting the signals in both protocol and data terms. So literally building a specialized third-party peripheral. It was always the interface hardware, that's what Game Freak told the magazines back in the day and what everyone who's dug into the problem finds.
