The iPhone is one of the most popular smartphones in the world. But that's not to say that it's perfect. One error that sometimes occurs with the iPhone is that it gets stuck on its boot screen (the screen with the white Apple logo). This is a bug that can occur as the result of jailbreaking the device, by downloading a new app or by updating an old app.
What you're experiencing when your iPhone gets stuck on the boot screen is a bug. This bug can result from corrupted apps, faulty updates or the jailbreaking process. When you power on your iPhone, the bug causes the boot process to get stuck in an infinite loop, therefore resulting in a static image of the white Apple logo.
The first -- and easiest -- troubleshooting method for a frozen iPhone is to reboot it. Do this by holding down the "sleep/wake" button on top of the device, while simultaneously holding down the "home" button (circular button with a white square in it). A red "power" slide will appear at the top of the screen. Slide this into the off position, and then turn your device back on. If the device stays stuck on the Apple logo after the restart, hold down the "sleep/wake" and "home" buttons for 10 seconds. This will cause the iPhone to reset. If it's still stuck on the beginning screen, try restoring the device.
An iPhone restore will most likely fix your problem. It does however carry the consequence of deleting all information that has been acquired since your last sync. To restore your iPhone, shut it off completely, and then open iTunes on your computer. Plug one end of the iPhone's USB cable into your computer. Hold down the "home" button on your iPhone while connecting it to the other end of the USB cable that's connected to your computer. Continue holding down the "home" button until the iPhone screen displays the "Connect to iTunes" icon. Your iTunes window should automatically navigate to your iPhone's screen, and a pop-up window will appear on your computer notifying you that the iPhone is trying to go into recovery mode. Click "OK" to continue. Click the "Restore" button on the iPhone page under the "Summary" tab. Wait for the restore process to complete before turning your iPhone back on.
It has been said that prevention is the best medicine. Keeping this in mind, it's better to avoid getting your iPhone stuck in the infinite "boot screen loop" than it is to restore your device. There are a couple of things you can do to avoid this problem in the future. Don't jailbreak your iPhone, and if you do, use only proven jailbreak methods. It should also be noted that while jailbreaking is legal, it does void your iPhone's warranty. Another thing you can do to avoid getting stuck in the boot up loop is to update your apps one at a time. Refrain from using the "update all" option in the App Store, as this has been known to causes crashes.