A colleague had been given an iPhone 4 previously owned and used by another colleague. After too many attempts at entering the wrong PIN code, the iPhone decided to deactivate itself. I was tasked with bringing this iPhone back to life.

This is the procedure I concocted, as none of the suggestions I found on the Internet worked:

  1. Ensure the iTunes application is up to date.
  2. Start the iTunes application and log out of iTunes as a precaution.
  3. Connect the iPhone 4 to the computer using a USB cable with a 30-pin connector at one end and a standard USB A connector at the other.
  4. Forcefully shutdown the iPhone by holding down the power and home buttons.
  5. Keep holding these buttons until the iPhone goes completely black.
  6. Keep holding the home button while pressing and releasing the power button.
  7. Soon you should see a screen indicating the iPhone is ready to talk to the iTunes application.
  8. Reset the iPhone to factory settings using the dialog boxes shown by the iTunes application.
  9. Enter the valid PIN code on the iPhone when asked to do so.
  10. If everything was successful, the iPhone should now behave like it was fresh off the assembly line.