Unscrew the four Phillips screws along the top of the back cover.

The screws are held in place by locking washers, and will not come out of the back cover.

Hold the device in one hand and turn it over.

Grab the top edge of the back cover with your opposite hand so that the cover does not fall back into place.

Flip the 3DS over again so that the back cover is facing up.

Pull the back cover up and away from the rest of the device to remove it.

Insert a plastic opening tool into the notch in the lower case above the battery.

Pry the battery up with the plastic opening tool.

Grab the top edge of the battery and lift it out of the lower case.

Remove the nine 6.3 mm black Phillips screws from the lower case.

Remove the 2.4 mm silver Phillips screw above the game cartridge slot.

Lift the bottom edge of the lower case off the rest of the 3DS.

There are still two ribbon cables connecting the mother board to the case, so be sure not to pull the lower case all the way off.

Use a plastic opening tool to pry the shoulder button ribbon cables off their sockets on the motherboard.

Remove the lower case from the device.

Remove the two 4.5 mm Phillips screws securing the SD board to the motherboard.

The connector for the SD board sits underneath the Circle Pad ribbon cable.

Use the flat end of a spudger to pry the SD board ribbon cable connector off its socket on the motherboard.

Insert the flat end of a spudger between the SD board and the motherboard.

Run the spudger along the sides of the SD board to free it from the adhesive pad holding it in place.

Once completely freed, lift the SD board straight off the motherboard.