HP ProDesk 600 G4 SFF Maintenance And Service Manual page 52

4. Remove the eight Torx-15 M3.0×9.0 screws that secure the system board to the computer chassis.
5. Swing the top edge of the lower cage (1) away from the computer chassis.
6. Remove the lower cage (2).
7. Lift the front edge of the system board (1) until it rests at an angle.
44 Chapter 4 Removal and replacement procedures