Progression
The I–bVII–IV–I in F# major
I–bVII–IV–I in F# major plays F#, E and B — I, bVII and IV — across 4 chords. The mixolydian rock cadence — a flattened seventh in place of the leading tone — behind riffs from classic rock to jam-band vamps.
The chords, in order
1F#I
2EbVII
3BIV
4F#I