Not too sure about emerald on a G6 flashcart but I can safely say that the R4 can recognise a real GBA game for link up. Worked with my real Advance Wars 2 and the Advance Wars: DS on my R4.Can R4DS recognize a GBA rom loaded in a slot-2 card? For example pokemon emerald on a g6 lite and pokemon diamond on an r4ds - will the R4DS recognize the GBA rom and allow me to use pal park feature.
Apparently it's not possible because slot2 flashcarts save differently (in their proprietary formats) from retail GBA carts
This is true for every game EXCEPT pokemon. The only way to get pokemon diamond or pearl to read the save from a flashcart is to use the EZ-V and the 3-in-1 expansion pack, and that only works because the EZ-V kernel patches diamond and pearl to read the different type of save.You CAN use a flashcard in slot 2 you just need one which has no firmware and needs a writer (like EZF ADVANCE III) and only write ONE Rom at a time.