Ah, that's nice to hear. Thanks!GB/GBC games read at 5v thats why when you add a led to the cartridge you have to add a resistor. So the GB one is fine, GBA games are 3.3 but i'm sure there is something to protect it since if you overload a gba game the system wont even try and read it.. And all improvements are listed on the site.
I remember reading an article detailing how EverDrives can actually cause damage to consoles via voltage difference (IIRC most of the consoles EverDrives are made for operate at 3.3V, and the EverDrive itself operates at 5V, leading to excess energy which could wreck your system).
Anyways. The cart itself looks cool. Don't know much about it, though. What improvements does it offer?