What is DFU Mode? ‘“ A How to Guide
DFU is an acronym used for Device Firmware Upgrade. DFU mode is often mistaken to be the same or similar to restore mode. So what does DFU mode do? DFU mode circumvents the existing Operating System installed. The process allows the device or your iPhone to downgrade or upgrade its Operating System. It should be noted that DFU mode is not a way of recovery. Recovery mode is very much different from DFU mode.

DFU mode is an option when you are getting or experiencing errors from your device. This is especially true if restore mode would not do the trick. Before performing the DFU mode, just be sure that no backlight is on. DFU mode is done without any backlight and the screen is at total blank.

Below are some of the ways to perform DFU mode:

Technique No. 1

• Connect your device to a computer
• Shutdown your device
• For ten seconds, hold or press the power and home at the same time. Be sure to do this for exactly ten seconds.
• At exactly ten seconds release the power button but do not release the home key. Wait until the computer beeps and the recognition of the USB device.

Technique No. 2

• Link up your phone to the PC while powered on.
• Hold power and home keys at the same time for about 10 seconds. Wait until the phone shuts off. When the phone powers on while holding the keys, you need to start over. This time hold the home and power keys in lesser time.
• Release power key and keep on pressing the home key. Wait until the phone is recognized by the computer.

Some users claim that technique number 2 is not a surefire way of performing DFU mode. There are reports that this method causes 1604 error during the restore.

Technique No. 3

• Connect the device to the PC
• Turn off the device/phone
• Press and hold power until the screen display turns on. As soon as the screen lights on, press home key and hold.
• For 10 seconds, hold both the power and home keys
• At the 10th second release the power but remain holding the home key. Wait until your PC recognizes the device. When you hear a beep, it means that the device has just been recognized.

If any of the three techniques fail to work, try adjusting the time of holding down the power and home keys. If 10 seconds fail, try over again and do it for 9 seconds. If it still not work, then try lessening the holding time until you finally get it to work. Sometimes it is just a matter of right timing to make the methods work.

There is another method if you are using a MAC Book slim or MAC OSX 10.5.6 and is having problem performing the DFU mode. Below are the steps necessary to perform:

• Sign up for a free account with Apple Developer Connection or ADC. It is advised to read carefully their terms and conditions before signing up. If you have future plans in developing application, then you may sign up.
• Once signed up, download the ‘IOUSBFamily Log release for Mac OS X 10.5.5 Build 9F33’ disk image.
• From the disk image, install the package.
• Perform a system reboot and you are done.