Simply boot up the Passcode tool and enter a password to get this trophy. Once you've obtained the passcode tool, you'll be able to find it by opening the map or the inventory and using the shoulder buttons to scroll to it. Once there, enter one of the following:
JUSTIN-BAILEY - Put Trace in his underwear.
REVEAL-SUDRAN - Translates Notes written in Sudran into English.
REVEAL-VYKHYA - Translates Notes written in Vykhya into English.
IKKIBU-LABIRU - Opens a path in the hallway north of the 2x2 room in the NW corner of Eribu.
DALKHU-SUBTUM - Opens a path in the 2x2 room in the lower left corner of Eribu
DINGER-GISBAR - Opens a path on the left side of Eribu. You'll need to go past the checkpoint, drill through a section of wall near the ceiling, and then keep going left until you find the Flamethrower weapon. Use this to get to the weapon.
ISKART-EHANZU - This opens a path to a blocked off area in the largest room in E-Kur-Mah.