Download this project and install the app on your iOS device. It will allow you to seemingly restart the operating system by simply opening the app!

Only works on iOS 7.1 with iPhone 5 or older (including iPhone 5c). i.e. it will not work on iPhone 5s.

The only lines of code that do anything in this app are the following:

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
  UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"MyCell" forIndexPath:indexPath];
  UIView *subView = [[UIView alloc] initWithFrame:cell.bounds];
  [cell addSubview:subView];
  
  // The following lines of code cause the crash, all three lines are required.
  cell.layer.cornerRadius = 1;
  subView.layer.shadowOpacity = 1;
  subView.layer.borderWidth = 1;
  
  return cell;
}

There may be other ways to acheive the same result, but by having these lines of code in the app, the app will cause SpringBoard to crash and restart, appearing to the average user that the operating system has restarted.

It's very simple when broken down:

• Dequeue a collection view cell in the usual way and add a subview to it
• Set the cell's corner radius to non-zero
• Set the subview's shadow opacity to non-zero
• Set the subview's border width to non-zero

Easy, huh? But by removing any one of these lines, the app will run normally with no effect on the processes of the operating system.

This works by taking advantage of a bug in backboardd, the daemon that runs alongside the SpringBoard daemon. The few lines of code in the app cause the daemon to crash, in turn causing SpringBoard to restart. The daemon has been witnessed to get into a state whereby this crash doesn't occur, and under such conditions, this app will not work. If this is the case for you -- and you have confirmed your device meets the Requirements -- please restart your device manually to witness this great app in action.

If you hadn't realised already, this is kind of a joke. I wouldn't expect an app of any size to cause the operating system to crash, least of all an app written in only 20 lines of code. Apple have been made aware of this and are investigating it.

Hopefully with this app in mind, if you notice strange things in your own apps causing the backboardd daemon to terminate after updating to iOS 7.1, you will be able to diagnose the problem more easily.

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