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Fastboot is a protocol used by Android to diagnose and flash new firmware images on Android devices via USB. It is part of the Android Debug Bridge (ADB). For Samsung devices, use [download-mode] instead.

What is fastboot intended for?

Fastboot supports a rather limited set of actions. Its primary uses include:

What fastboot does not do

Don't mis-interpret its name to be a "fast alternative to boot your device" (unfortunately, some manufacturers like HTC and Sony have a similarly named "Fast Boot" option). Admitted, a start into fastboot mode is faster -- but that's due to the fact it only needs a limited set of libraries etc. It does e.g. not start Zygote or the System Server (see: Can somebody explain the boot process of an Android device? -- that's what above mentioned "Fast Boot" option on some devices does for a "fast boot": killing the System Server; Unix-Users might compare that to killing the X-Server), so no GUI and no apps here. Neither does it offer a full set of commands (shell access) or the like. As described, it's just a very minimal system for a very specific purpose.

How do I get my device into fastboot mode?

Multiple ways for that:

  • when already connected to your computer via : adb reboot bootloader
  • with the device being switched-off: Press and hold volume up and power keys, release when boot completed (if that doesn't work, add the volume down button to the key combo, making it 3 buttons to simultaneously press-and-hold)
  • with the device being powered up in "normal mode" and the screen being switched on: long press the power button to bring up the power menu. Some ROMs have a shortcut here. On some, long-pressing the "reboot" option here brings it up.

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