Insert the flat end of a spudger underneath the motherboard, anywhere near the top edge of the phone.

Lift the spudger slightly to loosen the motherboard from the frame.

Remove the motherboard from the phone.

The underside of the motherboard is still connected to the phone by the daughterboard flex cable connector near the bottom. Lifting up on the motherboard should disconnect it. If not, use the flat end of a spudger near the connector to disconnect it.