Removing the motherboard will allow you to replace it, or give you access to the other components that are attached to it.
Turn the device so that the bottom is facing up.
Use the plastic opening tool to carefully lift the rubber stops in each corner.
Unscrew the 4 11.8 mm T-8 Torx screws from each corner of the device.
Lift the lower case straight up from the rest of the router.
Remove the clear plastic casing by lifting it straight up from the router.
Separate the motherboard from the top shell by lifting it straight up from the router.