Comment by travisgriggs

Small correction, I think. The booster appeared to survive hot staging fine. It went through quite a bit of it's flip back maneuver. It was awesome to watch. There were some interesting activations of engines in the booster engine ring at that point. It's unclear to me if that was anticipated as an offset subset was what was desired for the off axis maneuver, or things were degrading at that point. And then it blowed up, rather instantly. That something happened to the booster during the separation that led to its RUD ~20 seconds later is likely, but technically it was "long since separated" (in rocket launch time) when it was destroyed.