Is it possible to tell if a unjailbroken phone has been jailbroken in the past? I heard that a phone can be jailbroken and then "un-jailbroken." Is it possible to tell if an "un-jailbroken" phone has been jailbroken in the past?
If the device has been restored(how you "unjailbreak" a device), there is no way to find out if the device has been jailbroken in the past.