iPhone X for the motherboard chip the things in the phone will probably be cleared to zero, because it is to brush the system again, then a lot of things are gone if the chip is changed, even if you can ensure that you in order to your data security is also best to do a backup, because because there is no electricity, there are a lot of chips inside, storage will be cleared to zero again. And it does not retain data, so it must be backed up.