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
That’s pretty cool. I’ve seen people point out that Jyn’s theme is based in Dies Irae, which makes sense because there are a few direct quotations of it throughout the RO score, and of course SW before it (especially during Burning Homestead). I guess I never noticed it but that bit^ is definitely based in Dies Irae, which makes sense because it’s when Luke is rejecting his fate/destiny (which is of course flipped in the aforementioned Burning Homestead scene).
Oddly enough it’s the more subtle references to old Williams pieces that I appreciate (the obvious ones are hit and miss - I think the Force theme is overused and the Rebel fanfare and the original Imperial theme are underused). But the Dies Irae quotes are cool, as well as the couple Death Star motif bits, the flute hologram message motif, the Leia’s theme cameo, and the “Alliance Assembly” influence on “Scrambling the Rebel Fleet.” Giacchino is a huge JW/SW fan so I’m sure there’s more.