@ceralor not to mention literally unlocking the built in GBA backwards compatibility of AGB_FIRM (besides the 10 existing games for solely the ambassador 3DS consoles/accounts) is great, it's very similar to using Nintendont on Wii U to be able to play GameCube games with modern amenities like wireless controllers, virtual memory cards, and more. New Super Ultimate Injector can help immensely in that regard.

The only games that won't work correctly are games that require cartridge hardware (WarioWare Twisted, Boktai games). But you get perfect compatibility with everything else, as it is literally running a GBA in there--as the 3DS shares one of the same CPUs as the DS, which shares one of the same CPUs as the GBA!