When Hogarth lets the Giant into his garage after the train accident, as it reassembles its parts and repair itself. Hogarth notices the bolt by his foot and let's it pass underneath then the Giant picks it up and put it right back in the left side of its jaw making able to move it again.
Sometime after the Giant's sacrifice to save Rockwell from the missile, Dean gives Hogarth a package from General Rogard. That contained its' bolt being the only part the army manage to retrieve and wanted Hogarth to have it. Around nighttime, Hogarth awakes to find the bolt had gone but soon finds that its trying to leave, making him realize that it was being called, meaning that the Giant is still alive somewhere and helps it get outside as he opens the window for it, before being on its way and soon joins the other parts as their nearly to the Giant's head in some snowy region.