If you are using a Jailbroken iPhone, I am pretty sure that you are quite familiar with the word “DFU” mode. Device Firmware Update or DFU is the state or mode of your device (iPhone) when it has been turned on yet the device doesn’t load the operating system or boot loader to get it fully functional. The DFU mode is required to change the firmware of the device. Whether you want to upgrade or downgrade that’s relevant but it changes with the Operating system itself.
As the major mobile operating system (iOS) update gets released by Apple once in a while, most the cases they changes the firmware version of your device as soon as you install the updates. This procedure makes it nearly impossible to jailbreak or unlock your device. Because the jailbreaking technique works with certain firmware version and new firmwares are not jailbreakable in most cases. This is exactly where the DFU mode becomes more important for non-officially unlocked or jailbroken iPhone owners. For an example, Apple recently released iOS 5.1 which updates the firmware version on most of the devices (iPhone, iPad or iPod touch). If you update your device with 5.1 and later on you change your mind to go back to previous version, there is no way of going back. However, there are some tricky ways to go back which requires you to install previous version. This is where the DFU mode rises above many other factors.
How to Enter into DFU Mode
Step 1: Connect your iPhone with your computer and then Launch iTunes.
Step 2: Hold the Power button (top of your device) for sometime and turn it off following the on screen instruction.
Step 3: Now hold your power and home button together for 10 seconds and then release the power button. Don’t release the home button yet.
Step 4: Continue to hold down the home button until you see the following message from iTunes.Once you see this message, you know it for sure that your device in in DFU mode. However, always remember that the screen of your iPhone should be entirely black at this stage. Take a look at the picture shown below.
If you see different screen other than the black one, your device is not in DFU mode. If you see the iTunes logo and the cable on your screen, you must understand that this is normal recovery mode not DFU. So repeat the steps we mentioned above until you are on DFU mode. If you are new on this, you might need to take couple of shot but you will get there at some point.
At this stage you can do literally whatever you want. Either you want to install previous iOS or simply jailbreaking your iPhone you might need to go through this procedure. I am confident that this post will help you to better understand how to put your iPhone into DFU mode. Now, if for some reason you want to exit DFU mode follow the steps given below. Trust me, exiting DFU mode is not as hard as entering into it. So, here we go.
How to Exit from DFU Mode
Step 1: Take a look at the iTunes when you are on DFU mode, it will show your device is identified by iTunes. Now, hold the power and home button until your device icon vanishes from iTunes.
Step 2: As soon as it disappears from iTunes, release all buttons and wait.
You should see the apple logo within couple of seconds. The phone will automatically load the operating system as it would in normal mode. This is it. You are back to normal functional mode. I hope this post has helped you to get better understanding on DFU mode and how it works or how to get back to normal mode from DFU mode on your iPhone. If you like this post feel free to share. Ask questions from the comment section if you have any.