So that is what I'm saying here few pages back, but some people deny that is possible - with Nomad ending you are left with assumptions there are some people that might help. If Nomad have the hardware to surpass firewall of Blackwall, bring to life old tech (train station with perforated cards surely based on even earlier than 80s tech in real life) and if they can assembly old tank without any blueprints, they also may have highly skilled contacts with different point of view than Arasaka's techs. If you do not work on some project but just get the schematics you can see some backdoor that is hidden form guys that worked on it for many years. In Legend ending you have the promise form shady Mr. Blue Eyes, that we met only once if we are careful in Peralez questline, that he will help if you do another heist for him- but he might be Gaunter O'Dim of 2077 and he will help but only for huge price. In the Arasaka ending where you return to Earth you might come across to one of this to possibilities. If today not every terminal diagnosis have is precise why the Arasaka diagnosis or Alt prediction of the data (purposely I call it prediction because Alt is just AI) have to be just on point?