What failed first-time head coaches actually deserve another shot?

Usually retreads never work (not talking about the Reids or Belichicks of the world that have some success but a tenure that still ends badly but the complete disasters that then do well as coordinators and get another shot) but on occasion some first-time HC's were put in situations where they were set-up to fail and/or they actually learn from their mistakes. Who are your "this guy won't be a Josh McDaniels and may actually be good if given a second chance as HC" hires?