Bind them to the candidate, for some reasonable number of votes, and let the CANDIDATE throw his delegates to another candidate if he sees he's not going to win.
I voted for a candidate, not a delegate.
This would be a fairer system. The only weakness is that it might still be a deadlock in the second phase. Maybe there could be a third phase if the candidates can't deadlock when throwing delegates, where the delegates can break it. But if so, those delegates better be people who were loyal to the candidate coming in, so I think should be chosen by the candidate and from the area they represent...what I find infuriating is this last principle being violated combined with the delegate having real deciding power, because as you said the people voted for a candidate--and that is like changing people's votes rather than just reaching a compromise in a simulated run-off.