My reccomendation is that you don't downgrade. I know you can get custom firmware that lets you play the new games and browse the internet, but Sony keeps releasing new features and demos that really make downgrading pointless. The emulator is nice, but if you want an emulator, a safer and better way is to import a special cartridge for the DS that is like a micro SD adaptor which allows you to run emulators (for a variety of previous gaming platforms) as well as actual DS games, on the DS safely.