It is used for slot-2 users so they do not need to have a PassMe. It also provides protection against the two DS viruses. It also allows you to take away the spalsh screen and the beginning of booting up. Alternativly if you have a slot you can use the No Auto-Boot version which boots to Slot-1 instead of Slot-2. The worst thing that will happen if you flash your DS is that you will brick it if you screw it up. For more info just google 'FlashMe DS Firmware Hack'.
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