iOS 7, iPhone 5C, jailbroken - tried to restore to factory settings but it hangs in iTunes

Even in DFU mode, iTunes recognizes the iPhone. Before you can restore, iTunes makes you download the new iOS 8. iTunes stalls on "Installing 1 update (10 hours remaining)" It's been at this screen for 3 days now...no progress. Occasional error messages (always different - one was Error -39). Now what??