An assembly method suitable for assembling a portable electronic device having a housing with an undercut portion is disclosed. The method includes aligning a non-display portion of a display assembly with the undercut portion of the housing, the display assembly comprising a display, a protective top layer covering a top side of the display portion and the non-display portion and a battery module attached to an underside of the display assembly, electrically connecting the battery to a circuit previously installed in the housing, angling the display assembly in relation to a front opening of the housing in a tilted configuration such that the non-display portion is partially inserted into the undercut portion of the housing, and in the tilted configuration, performing a pre-install functional test on the display and fully inserting the display assembly into the housing only when the pre-install functional test is successfully completed.