Back to the topic of Giacchino’s score, I found this bridge at 3:30 in “Tales of a Jedi Knight/Learn About The Force” from the Star Wars '77 soundtrack, it’s exactly the Jyn Erso theme from RO, take a listen:
https://youtu.be/soNidwqk1U4?t=3m30s
Personally, I think that section sucks as a main theme, it’s too simplistic, but it does sound like it was actually a callback to the original score for ANH.
Edit: It seems someone in the YouTube comments beat me to it