Here's another method for making the back of an iPhone:

First of all, draw one quarter of the top top profile with the freehand curve tool. Having it be a single curve instead of using fillets will create a surface that's easier to work with later on.


Then, draw an arc in a side view. This will create the chrome ring on the iPhone.


Sweep the arc along the curve we created in the beginning.


Mirror the surface until you have the complete ring. Once that's done, join the surfaces together.


Now, use the new Nsided command to create the dome.


Adjust the dome bulge parameter to size, and you're done! For this example, I set the dome bulge to 0.25.