|Trophy: Open Sez Me|
|Complete "Open the Precursor door".|
Open the Precursor door is a mission in The Precursor Legacy that Jak and Daxter complete to earn a power cell. Taking place at Geyser Rock, it is part of the training course required by Samos Hagai at the beginning of the game. It introduces Jak to blue eco and its ability to activate dormant Precursor artifacts, in this case a door.
After a little practice with the blue eco clusters, you will reach a cliff with a large Precursor door. Samos will tell you that you need to channel blue eco in order to open it. Approach a wooden bridge on the opposite end of the cliff, at the end of which lies a blue eco vent. Doing so will trigger a cinematic in which Keira explains the purpose of eco vents, after which you may walk into the vent to receive a maximum charge of blue eco.
Then, simply walk back to the door before the charge wears off, at which point the blue eco will cause it to open. Lastly, collect the power cell on the other side of the door. Note that you can instead use the blue eco clusters from before to open the door, though using the vent is easiest.