Do any of the GBA carts work with the Gen 4 Pokemon PAL Park feature? Or is there a different flashcart that works aside from Reproductions / Original Game Cartridges?
It will not work with PAL park. I believe the EZ-FLASH OMEGA Definitive Edition can use its "Mode B" but the build quality isn't great with those and there are a lot of reports of people losing saves.
The other option would be something insidegagets flash cart but that also needs their flasher.
Dang, that's a real pretty penny for the InsideGadgets route!
Still, that's good to know that a decent DIY option exists for those that want to play the GBA Pokemon games without gambling with Reproductions or paying out retro scalpers.