HP ProBook 4540s Notebook PC HP ProBook 4440s Notebook PC HP ProBook 4441s Notebook PC - Maintenance and Service Guide

5. For 4540s models, remove the following screws that secure the top cover to the computer:
(1) 4 rubber screw covers from the corners of the computer
(2) 11 Torx T8M2.5×6.0 screws
84 Chapter 4 Removal and replacement procedures