Turning an iPhone into a Mupi

What this does

A supervised iPhone can be told to run one app and nothing else — Apple calls it Single App Mode. Turn the phone on and it is in Mupi. There is no home screen to get back to, no App Store, no Safari, no Settings, and it stays that way through a restart. The phone stops being a phone and becomes a camera that happens to be made of one.

Before you start

• The phone is erased. Supervision can only be applied to a phone being set up from scratch. Do not use one with anything on it you want.
• You need a Mac with Apple Configurator, which is free from the Mac App Store, and a cable.
• Give yourself an hour the first time. Twenty minutes of it is the phone restoring.
• If this sounds like more than you want, use Guided Access instead. It is two taps and undoes itself, and Mupi behaves the same way inside it.

Step one: supervise the phone

1. Install Apple Configurator on the Mac and open it.
2. On the iPhone, turn off Find My — Settings, your name, Find My, Find My iPhone. A phone with Activation Lock on cannot be prepared.
3. Erase the iPhone: Settings, General, Transfer or Reset iPhone, Erase All Content and Settings.
4. Connect it to the Mac. It appears in Configurator. Select it and choose Prepare.
5. Choose Manual Configuration and tick Supervise devices. Leave enrolment in an MDM server set to none — you are not running a school.
6. Create a new supervision identity when asked, and keep it. It is what lets this Mac change the phone later.
7. Let it finish, then walk through iOS setup on the phone itself and sign in to iCloud so photos can back up.

Step two: install Mupi and let it set itself up

1. Install Mupi from the App Store on the phone.
2. Open it and go through setup: say the phone is for a child, give them a name, and let them pick how the camera looks. Do this before locking the phone into the app — once it is in Single App Mode you cannot get to anything else to fix a typo.
3. Take one photo and check it appears in the family library on your own phone. If it does not, the camera is not signed in to the right iCloud, and that is far easier to sort out now.

Step three: lock it to Mupi

1. Connect the phone to the Mac again.
2. In Configurator, select the phone and choose Advanced, then Start Single App Mode.
3. Pick Mupi from the list.
4. Open Options before confirming. The one that matters is Device Sleep — leave the sleep/wake button enabled and the side button puts the camera to sleep the way it normally would. Turn it off and the button does nothing at all, which on a phone a child carries in a bag is not what you want.
5. Confirm. The phone restarts into Mupi and stays there.

To undo it

Connect the phone to the same Mac, choose Advanced, then Stop Single App Mode. It needs the supervision identity created in step one, which is why keeping that matters. Supervision itself is removed by erasing the phone.

Worth knowing

• This is Apple's supervision, not something Mupi controls. Mupi is simply the app you point it at, and it behaves the same way it does inside Guided Access: the camera sleeps after 45 idle seconds, and the hold to reach the family library is longer.
• You can still get to the family library. Hold the camera header for three seconds and use the device passcode. Mupi deliberately keeps that door on a locked-down phone — one with no way back is one you can lock yourself out of, recoverable only by erasing it.
• No FaceTime from a locked phone. Same reason as Guided Access: iOS does not let one app open another. A child can still take a photo and send it to a grown-up, which reaches them through a locked phone with no signal.
• A dedicated camera does not use less battery by itself. Mupi stopping the camera when it is idle is what actually helps, and that happens in Guided Access too.
• Updates still install from the App Store, but you will have to leave Single App Mode to do it. Worth doing every few months rather than never.