Steps after buying a used iPhone I'm buying a used iPhone.  What steps should I take immediately after I receive the iPhone, to make sure that everything is OK, that I got what I paid for, and that I'm not receiving a lemon?

For instance, it might be nice to check that it wasn't reported stolen / blacklisted.  Also, I am buying a factory unlocked phone, so it'd be useful if there is an easy way to check to make sure I am receiving an unlocked iPhone.  Also, if there is any hardware that is frequently broken / not working on used devices, it might be useful to have a checklist for checking that hardware.



Related, but not identical:


What to ask when buying a used iPhone 4, though that's different: it focuses on deciding whether to buy or not, and what to ask to help make that decision.
What are the steps to transfer an iPhone to someone else?, though that's different: it focuses on the seller's perspective and has a complicated scenario, whereas I'm interested in the buyer's perspective and have a simple scenario.
How to know where and when my iphone was bought?
Steps to be done before selling your iPhone
Find out if my iPhone is unlocked without purchasing another SIM
Once you get your hands on the iPhone, put your SIM card in it, do a full reset, and after it restarts go through the initial setup phase - until you get to the main screen with the apps on it.

Make sure you have a mobile phone signal (3G or 4G or whatever). That will tell you that the phone will work with your SIM.

It will also have activated the phone during that initial setup.

If the phone was previously assigned to another iCloud account, it may prompt you for the password for that account during that process. If the seller does not have the password, hand the phone back because it's a brick. And probably a stolen brick at that.

After that, you're pretty much OK.