By completing the quest "Institutionalized" as suggested you should have free access to the Institute. Time to make use of it and - since you've decided to side with the Brotherhood of Steel - talk to Doctor Li, who can be found in the Advanced Systems section of the Institute. Put on all of your Charisma gear for several speech checks... it is probably a good idea to take a day-tripper or whatever other drug you have that will up your Charisma score as well - the hardest speech check here (to actually convince her) is red, so more Charisma will force you to load fewer times.
Save and then talk to Madison. Be upfront with her and tell her the Brotherhood needs her. You can get your first speech check here by asking her if she is "Happy here?", which gives you a window of doubt from her (which is all a smooth talker like you needs!). Still, she assumed the BoS would want her dead, so why come back? Two more speech checks happen after that question, namely "Trust Me" and "We Don't Lie", both moderate speech checks. Pass both of those and then the last remaining speech check remains, the line to convince Madison Li to come back, "Free the Commonwealth", which is a hard speech check but passable with all your Charisma gear and drugs! Heh. Pass that and she will agree, telling you to tell Maxson that she is on her way.
Before you report back to Maxson, however, give the "Network Scanner' holotape to Proctor Ingram to complete the quest "Out of the Wire" . Once done, report to Elder Maxson back on the Prydwen once you are done and he will be impressed. The quest "From Within" will end shortly after that and "Liberty Reprimed" will begin.
You will be told by Elder Maxson to go talk to Proctor Ingram as she needs your help. Ingram is located at the Boston Airport, so head down there and talk to her. She will take you to the room where the Brotherhood team is working on rebuilding Liberty Prime. Yes, they are rebuilding it, because of course they are. Ingram will tell you that they need Dr. Li to help with a power issue, but she is hesitant to work on the robot so she wants you to talk to her.
Put on your Charisma gear once more and head back to the Prydwen. Doctor Li is on the main deck, so go talk to her. She knows what you are here for, but pick the "Remind you?" moderate speech check to pass it, get some quick XP, and get Doctor Li back on the project. Head back to the Boston Airport now and report to Ingram, who will ask for your help with another issue: building electromagnetic actuators for Liberty Prime. Wait, what? Yes, you are going to build four of these things but first you need to go retrieve a "High-Powered Magnet" from a hospital before you can build the actual device (some other teams are getting some other "High-Powered Magnets" for you, so you just need to get one thankfully). If you already have a "High-Powered Magnet" from your travels (perhaps your earlier exploration of Mass Bay Medical Center?) you can obviously skip the next bit. If not... well, here goes.
Getting a High-Powered Magnet
You now need to head to the "Medford Memorial Hospital", which is near Malden Center, north-east of Covenant. You should know what awaits you here: Super Mutants, especially obnoxious Suiciders outside and inside, in the lobby. Clear out the Super Mutants and make your way up to the Operating Theater on the third floor, wherein you'll find a Trunk containing the High-Powered Magnet you need. Grab it, then return to Boston Airport.
No point in talking to Ingram or Dr. Li; you still actually have to build four Electromagnetic Actuators! Head west of the Fast Travel spot and follow the objective marker to the workbench of the airport. Interact with it and start to clear out the area, scrapping the broken terminals, tires, cans... basically everything but the counters, carpet and seats (or y'know, just scrap whatever you wish!). If you have to go outside exploring to get the rest of the parts do so, or buy junk from merchants with the correct components in them.
Once you've done that, pick the "Special" tab in the settlement crafting menu. You should have five High-Powered Magnets here and enough screws, fiber optics and circuitry to just barely build four of these things. Build all four (where you build them doesn't matter) and the exit the workshop. Go talk to Ingram now and she will be glad, but will assign another mission to you: finding Liberty Prime a stockpile of nukes (he apparently can't use all those Mini Nukes you found not too long ago!). You are told about a stock in the Glowing Sea that they have on record, and to go talk to Scribe Haylen at the "Edge of the Glowing Sea" before you head out.
Note: As always, if you are going to visit the irradiated wasteland that is the Glowing Sea, remember to bring your suit of Power Armor and enough Fusion Cores to last awhile.
Edge of the Glowing Sea
Head out to the "Edge of the Glowing Sea" now (which you can fast-travel to from your first visit there) and find and talk to Scribe Haylen at the edge before you go in (they have actually set up a new waypoint out here, "Waypoint Echo"). You can get an update on Cambridge Police Department but she'll soon give you the "Distress Pulser" to use once you have found the bombs. She'll also warn you about the radiation.
The place you need to go to is "Sentinel Site Prescott" (or just "Sentinel Site"), which if you've done the "Exploring the Glowing Sea" section of the guide you should have already cleared. It is the pyramid-looking structure south of the "O'Neill Family Manufacturing" location, east of the "Rocky Cave" where you found Virgil (and one of the most southern points on the map).
Enter the building and clear out any beasties that dared to respawn, then head down to the bottom of the area you enter into (if you're in Power Armor, you can just jump to the bottom and save yourself some time!). Head into a tunnel to the east then follow some winding side-tunnels to the north to reach the room with the elevator.
Now, this is the point where the area changes! If you are here for this quest, the door by the computer console near the crate elevator is accessible (it won't be if you aren't here for this quest - it was blocked by a steel shelving unit before this). Put on your Charisma gear at this point and save. Inside is a Child of Atom named Henri who will ask what you are doing here. You can choose to tell him you are here for the bombs which will eventually cause a moderate speech check ("Spread His Glory") to appear. Passing it will grant you "Henri's Terminal Password" (even if you don't pass it you get a second chance with another moderate speech check). Or, you could just take him out but you would also have to take out the Assaultron and the Machine Gun Turret. Either way, loot the room afterward to find "Captain Dunleavy's Holotape" and a suitcase [Novice] you can pick. Use the terminal once you are done to open the door down below.
Inside you will find... the motherlode of nukes. Even more than you found at Fort Strong earlier! You can find a Mini Nuke on the right in a crate, but after grabbing it place the beacon on the nearby forklift and then talk to Paladin Danse. He will stay behind to guard them. Leave via the crate elevator in the next room and fast travel back to Ingram.
As you can see when you arrive, Liberty Prime is fully built. Just keep it away from orbital strikes this time, eh Brotherhood? After talking about the machine's capabilities for a bit you will be asked to turn it on. Go ahead and do so and listen to its warm-up routines. After booting up you can talk to Proctor Ingram to be rewarded with a "T-60 Medic Pump" for your efforts. Once Proctor Ingram is done talking, the mission will officially be over. Wait a few moments and the next mission, "Blind Betrayal", will start.
|For getting Liberty Prime up and running again||700 XP|