[Noob-Friendly] The difference between DFU and Recovery Mode

Discussion in 'General iOS discussions' started by mikeac, Jul 7, 2010.

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  1. mikeac

    mikeac Member

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    *Sweet! On the front page news!

    Restoring is the most common way to fix your iPod. Also, it is used in jailbreaking and downgrading, and is a common subject mentioned in pretty much every single website that deals with iPods, iPhones,and iPads. Here is a simple explanation of what restoring does by spoonforknife: "Restoring and You"

    To summarize that guide, restoring resets all your settings and removes all your apps. It is not recommended if you can figure out what else is going wrong in the iPod and fix it.

    And there are two different methods in which you can restore from, as shown below in the pictures. DFU (Device Firmware Update) and recovery mode.

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    So, what is the difference? They both allow you to restore, and both can be entered in through a similar series of button presses. They appear to exactly the same, but really, there is a major difference.

    You did notice that DFU mode appears off, and the only way you could tell if DFU mode is active is if you plug it in the computer and it will tell you that it is in recovery mode. There is a reason for that.

    Noob-friendly explanation:
    When entering recovery mode, the program that fully starts up the iPhone/iPod is active, so the back-light is on and you can see the connect to iTunes logo. That program, along with iTunes, also prevents downgrading or jailbreaking your device, and limits the device to restore to a valid firmware.

    However, when entering DFU Mode, the program that starts up the device is inactive, causing it to appear off, yet it is still able to be recognized by iTunes. Without fully starting up the device, you have the ability to jailbreak your device when other requirements are met**.

    Technical explanation:
    (This uses some tech jargon.)
    When entering recovery mode, the iBoot bootloader is fully active, allowing the iS to load in recovery mode, resulting in showing showing the Connect to iTunes icon. The iBoot bootloader is also what prevents exploits like the popular 0x24k segment overflow (24kpwn) to work, and allowing you to only flash a current or newer firmware update.

    However, when entering DFU mode, iBoot is inactive, so the iOS isn't loaded, causing the device to appear off, but it is really in device firmware update mode. Because of the lack of iBoot and the iPhone OS, exploits can be loaded and the firmware restriction is lifted, so you can easily jailbreak or restore to a custom firmware when other requirements are met.**

    SHSH Blobs:
    When saved, these helpful little thingies allow you to restore to a previous firmware in Recovery mode. For more information, check out the links below.
    SHSH Blobs FAQ
    Intro to SHSH

    How to...
    ...get into recovery mode:
    You can also use iRecovery or RecBoot.

    ...get out of Recovery mode:
    1. Make sure your device is unplugged.
    2. Press Home and Power for ten seconds.
    3. While the device is rebooting, let go of the power and hold the home button. It should boot up normally.

    ...get into DFU mode:
    1. Make sure the iPod is off and plugged in.
    2. Hold the power button for three seconds.
    3. Hold the home and power button for ten seconds.
    4. Release the power button and hold home until your device is recognized in iTunes.

    ...get out of DFU mode:
    1. Make sure your device is plugged in.
    2. Press Home and Power for ten seconds.
    3. The device should power off, and it will disconnect from the computer. You can power on normally now.

    ...Restore your device:
    1a. Press Restore in iTunes while in DFU/Recovery Mode and connected to computer.
    1b. (Custom Restore) Press Shift and Click restore and select an .ipsw to restore.
    2. It will erase everything on your iPod and replace it with the latest Stock Firmware.
    3. It will take a while, when it is done, you can restore from a backup and resync.

    ...Recover from Recovery Loop:
    Option 1: Grab TinyUmbrella and Click Exit Recovery mode.
    Option 2: Restore.

    Sometimes you may get an error trying to restore. Reboot and try again.
    If your device is not detected, reboot your computer, reinstall iTunes, or try another computer.
    If your device cannot enter DFU mode, it is a hardware issue. Get it fixed or buy a new one.

    *Most of this information was received from the iHackintosh explanation. Other sources were this site and the iPhone Wiki.
    **By other requirements I mean programs, .ipsw files, SHSH blobs, etc. that are needed to downgrade or jailbreak your device.
  2. Fishy

    Fishy Member

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    Sweet, this will help a bunch of people. I'll be sure to redirect to this when needed. J-phone, nont post simply for post count.
  3. SilentWalker

    SilentWalker Retired Moderator

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    Very helpful. Thanks a lot. I can't even remember how many times I searched and searched for something like this but never found it in one complete guide. This should help many people.
  4. Asakura_Hai88

    Asakura_Hai88 New Member

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    Sry pardon me for being noob, does it mean that going into the DFU mode, we'll be able to reset the device? will it swipe out everything while keeping the same firmware ver and the jailbreak?
  5. peebrian202869

    peebrian202869 Banned

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    It will destroy everything.
  6. Sketchy

    Sketchy Member

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    Great Post Thanks Alot, and this will Help a lot of people too!
  7. Axis

    Axis Super Moderator Staff Member

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    thread cleaned up a bit and stuck.
  8. tanktan38

    tanktan38 Active Member

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    So I can put my device in DFU and downgrade to any firmware without the SHSH blobs for it... yea... no.
  9. mikeac

    mikeac Member

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    If you have an MB model device, then probably yeah.

    But thanks for pointing that out.
  10. iBricked

    iBricked Well-Known Member

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    So after reading this people refering to DFU mode were actually talking about recovery mode? ...
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