Android Flash Tool

Android Flash Tool allows you to flash an Android build to your device, usually for development or testing. To get started, you need a development machine and an Android device.

Development machine requirements

Your development machine must meet these requirements:

  • Browser: Any browser supporting WebUSB, such as Chrome or Edge 79+.
  • Platforms:
    • Linux
    • macOS
    • Chrome OS
    • Windows (requires an additional USB driver)

Installing Windows Drivers

To work with fastboot and flash devices on a Windows machine, you need a customized USB driver from the Android SDK. For more details, see Install OEM USB drivers on the Android Developers site.

adb kill-server

Device requirements

You can flash a new version of Android to these supported devices:

  • Pixel 2
  • Pixel 2 XL
  • Pixel 3
  • Pixel 3 XL
  • Pixel 3a
  • Pixel 3a XL
  • Pixel 4
  • Pixel 4 XL
  • HiKey
  • HiKey 960

Preparing your device

Before you can flash a build to your device, you must prepare your device:

  1. Enable Developer options and USB debugging.
  2. Enable OEM Unlocking in the Developer options menu. If your bootloader is already unlocked, this option is grayed out with Bootloader is already unlocked.
  3. If you're having trouble enabling OEM Unlocking, make sure:
    1. Your device is connected to the internet
    2. Your device has checked in with Google, which may not be the case if your device recently connected to the internet. To force a check in, enter *##CHECKIN##* (##2432546##) in the Dialer (no SIM required). After entering the number (no need to press call), the text disappears and a success notification appears.
    3. Some devices require carrier intervention to be unlocked. Contact your carrier for more details.

Flashing your device

  1. Connect your device directly to your development machine (no hubs, adapters, extenders, or monitors).
  2. Open in a browser on your development machine. It opens to the welcome page.
  3. Allow the flash tool to communicate with your test device through adb, by accepting the popup that says Allow site access to your ADB keys in order to communicate with devices.
  4. Select Add new device.
  5. Select your device from the list and click Connect. This list may not contain the full device name.
  6. On your device’s screen, select Always allow from this computer and click OK to accept the USB debugging connection.
  7. Select the connected device in your browser.
  8. Search for and select your desired build from the list.
    1. You can also select options, such as wiping the device or force flashing all partitions.
  9. Click Install to start the process. The device reboots and enters fastboot mode. Note: If this is the first time you're flashing this device on this machine, your machine loses the connection to the device and asks you to find it again. The next time you flash the same device on that same machine, you won't see the request to refind the device. After reconnecting, the flashing resumes and starts downloading the images and performing all the required steps.
  10. After Flash Complete appears, disconnect the device from the USB cable.

USB transfer errors

Sometimes Android devices have trouble communicating through certain USB ports or hubs due to the high throughput of data. To improve reliability:

  • Don't use USB hubs. This includes connections through monitors.
  • Don't use USB extension cables or adapters if possible.
  • Try a different USB port. Rear ports are often more reliable than front ones.
  • If you're using a USB C port, try a USB A port instead.