On Fallout Wiki I read this:
But it's written pretty badly and I'm not able to understand exactly what I should do...
Yeah, the Wiki isn't exactly in the plainest English, but I can confirm that the fix does indeed work.
Had the same problem as everyone else here in that the game would just freeze on the third ED-E dialogue.
In simple terms, what you need to try and do is arrange it so you are standing next to Senior Knight Lorenzo while he is asleep. Then just as ED-E is about to enter his dialogue, wake up Lorenzo. While he is in the process of getting out of bed and standing up, ED-E will do his third dialogue thingy, then afterwards rather than simply freezing, Lorenzo will now talk to you instead.
It all sounds simple (hopefully), but the real trick is in the timing. Make sure you save loads. Took me quite a while to setup as ED-E would keep catching me up and the game would then freeze.
Anyway, hope this helps.