Sun Microsystems Sun Enterprise 250 Guide De Montage page 14

3. Loosen the two captive screws securing the side panel to the rear of the chassis.
4. Pull the side panel toward the back of the system.
Carefully disengage the hooks securing the side panel to the top of the chassis.
5. Lift the panel up and away from the system.
How to Rackmount the Sun Enterprise 250 Server 1-9