How to Download and Manually Install Android 5.1 Lollipop

Google on Monday began rolling out the first major update to its Android 5.0 Lollipop operating system. The update, Android 5.1 Lollipop, will be rolled out to various devices, with the Nexus series the first in line to get the latest version. The Nexus 5, Nexus 7 Wi-Fi and the Nexus 10 are the three devices that will get this update first as Google posted Android 5.1 Lollipop factory images for these devices on its website. If you can't wait for the OTA update to arrive, you can use these images to install Android 5.1 Lollipop on your device.

You can manually download and install the Android 5.1 Lollipop factory image from Google's website. This process is not recommended for anyone but the most advanced users who have a bit of technical know-how. This process will erase all your data, so make sure you back up your Android device first. If you understand the risks and own a Google Nexus 5, Nexus 7 Wi-Fi or a Nexus 10, you can use these steps to flash the latest version of Android Lollipop on to your device.

1. Download and install the latest Android SDK on your Windows computer. This installs two programs, ADB, and Fastboot, which can be accessed through the command terminal on your PC, as a part of the software development kit.

2. Add the SDK folder to the PATH by following these steps:

• Right click My Computer and click on Properties. 
• Click on Advanced System Settings. 
• Click on System Properties > Advanced > Environment Variables. 
• In the window, select Path, then click on Edit, and then type in the name of the directory where you installed the SDK, and remember that each entry is separated by a semi-colon.

3. Enable USB debugging on your device. First, go to Settings > About Phone > Software information.

4. Tap Build number seven times.

5. Go to Settings > Developer options. Tick USB debugging.

6. Download the correct factory image for your device.

Android 5.1 Lollipop for Nexus 5

Android 5.1 Lollipop for Nexus 7 (Wi-Fi)

Android 5.1 Lollipop for Nexus 10

7. Extract the image on your computer.

8. Connect your device to your computer over USB.

9. Start the device in fastboot mode.

For Nexus 5, hold the volume up, volume down and power buttons while powering on the device. The full list of key combinations for different devices can be found here.

You can also boot into fastboot mode using the ADB tool: With the device powered on, go to the command terminal and execute the following: adb reboot bootloader

If needed, unlock the device's bootloader through your computer using the command terminal and executing: fastboot oem unlock

1. Open a command terminal and navigate to the unzipped system image directory.
2. Execute flash-all.bat, which was a part of the unzipped image file. This script installs the necessary bootloader, baseband firmware(s), and operating system. For this to work, you need to have added the folder where ADB and Fastboot are installed to the system's path as described in step 2.
3. When this is done, Google recommends that you lock the bootloader for security. You can do that by booting the device in fastboot mode while still connected via USB, and using the command terminal to execute: fastboot oem lock.

While this method will install Android 5.1 Lollipop on your Nexus device, we still suggest that you wait for the OTA update to ensure a hassle-free update process.