DFU vs Recovery mode iOS devices

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DFU vs Recovery mode iOS devices

To understand what DFU is on iOS devices, we need to understand how iPhone works, especially how Apple’s secure boot chain works to prevent loading anything that is not signed by Apple.

  1. Bootrom, which is embedded within the processor of the iOS devices, contains a public key that is required during the power-up of the device. The public key is then used to verify with a low-level Bootloader that is assigned by Apple before allowing the device to load.
  2. Bootloader, contain a piece of code that is run whenever the different hardware circuits are getting power, on the motherboard. There are two factors here: LLB (Low-Level Bootloader) and iBoot. LLB which is the lowest level bootloader runs several firmware checks and verifies iOS Kernel signature. If this verification fails, the device goes to Recovery Mode that is visible on the screen. However, if LLB or iBoot cannot verify iOS, it will automatically put the device in DFU.

DFU Mode

DFU stands for Device Firmware Update, as the name suggests. In the DFU mode, we can flash not only iOS but force flash iBoot/iBSS (iBoot Single Stage) bootloader. in case of iBoot corruption since in the Recover mode the iBoot/iBSS only gets flashed when the version differs from what it has already.

  • When the device is in DFU the screen will be blank. If you see anything on your iPhone screen means it is not DFU mode.
  • When in DFU iTunes will tell you the device is in Recovery mode that is not true? If your device screen is all blank, you are fairly sure that it is in DFU mode. However, if you are not sure and want to confirm this, you can use 3uTools it will tell you if it is in DFU or Recovery mode.
  • You can enter and exit the DFU state easily without breaking your device.
  • You cannot upgrade iOS and retain your data on the device as done in normal mode and recovery mode. That is technically not true where 3uTools is concerned, as you can use the retain user data option. What it does is to update ramdisk in place of erasing the ramdisk. You can do the same with iTunes with a modified IPSW. You modify the buildmanifest.plist to reference the update ramdisk instead of the erase it, then perform a restore as usual with the re-compiled IPSW. There is a python script that does it too make-no-erase-ipsw

Recovery mode

The Recovery mode is designed to update and upgrade iOS whenever you update or upgrade iOS via iTunes or in the settings. The iPhone enters recovery mode before doing the update or upgrade (Even though you don’t see the recovery mode displayed on your iPhone. Recovery mode is only seen on the iPhone when you manually enter to recovery mode or the iPhone goes automatically to recovery mode because of some fault in the firmware). In Recovery Mode, it is keeping all your data if you choose to do an update only.

How to put iPhone to DFU

iPhone 5/ iPhone 5C/ iPhone 5S/ iPhone SE

  • Connect the lighting cable to your iPhone and computer.
  • Hold the power button and home button till the screen goes black.
  • Then count to 2 seconds and release the power button while holding the home button.

Congratulations, you are in DFU mode, to get out of the DFU mode. Hold down the power button and home button together for 10 seconds and you should be back to normal.

iPhone 6/ iPhone 6S

  • Connect the lighting cable to your iPhone and computer.
  • Hold the power button and home button till the screen goes black.
  • Then count to 2 seconds and release the power button while holding the home button.

Congratulations, you are in DFU mode, to get out of the DFU mode. Hold down the power button and home button together for 10 seconds and you should be back to normal.

iPhone 7

  • Connect the lighting cable to your iPhone and computer.
  • Hold the power button and volume down button till the screen goes black.
  • Then count to 2 seconds and release the power button while holding down the volume down button.

Congratulations, you are in DFU mode, to get out of the DFU mode. Hold down the volume down and power button together for 10 seconds and you should be back to normal.

iPhone 8/ iPhone X/ iPhone XS/ iPhone 11/ iPhone 12

  • Connect the lighting cable to your iPhone and computer.
  • Volume up (Press one time)
  • Volume down (Press one time)
  • Hold the power button for 9-11 seconds the moment the screen goes blank.
  • Let go of all buttons for a split-second.
  • Then hold the volume down and the power button for 5 seconds.
  • After 5 seconds, release the power button and keep holding down the volume down button. Till iTunes recognises the iPhone in DFU mode.
  • Worth mentioning, for anyone who does microsoldering, Hydra devices, so iPhone 8 onwards, actually have a FORCE_DFU test point. In the case of the worst corruption, you can inject 1.8v into the test point prior to connecting cable, which forces DFU. We recommend you solder a magnet wire to the test point and inject 1.8v from your DC Power Supply. As soon as you connect the Lighting cable to the iPhone. Using the output On/ Off button on your DCPS cut the power.

To exit DFU mode. Volume up (Press one time) and volume down (Press one time) then hold the power button till you see the Apple logo


Reviewed and edited by Microsoldering from Mobile Repair/ Discord Channel. Images from pexels.com edited by us.

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