Nexus 5 and Nexus 7 Android L Beginner's Guide: How to Install and Use
Google has issued the Android L beta vesion. While Google has to provide an official name yet for the platform, people can install it on their Nexus 5 or Nexus 7 device.
However, people should be careful. According to Google: "The Android preview system image is not a stable release, and may contain errors and defects that can result in damage to your computer systems, devices, and data. The preview Android system image is not subject to the same testing as the factory OS and can cause your phone and installed services and applications to stop working."
Here are the steps to installing the Android L on Nexus devices.
Step 1: Download the small 2MB installer from this XDA thread. This includes the Android ADB and fastboot tools. These are necessary to install the Android L Image. They also offer the quickest way to install these tools without downloading the entire Android SDK. The Android SDK file may be too large with contents not relevant for installing Android L.
Step 2: Follow the instructions. DO NOT change the installation path when asked where to install it, and users should wait for command prompt to show up.
Step 3: Download the appropriate file for your device
Nexus 5
Nexus 7
Step 4: Head to the Settings on the handset, and scroll down to the About Phone down at the bottom. Look for Build Number and tap it 7 times. This will reveal the Developer Options that are not displayed on Android 4.2 and later. Enable USB debugging on the Developer Options menu.
Step 5: Download the USB driver from here ->http://developer.android.com/sdk/win-usb.html# and extract the .zip file.
Step 6: Go to the control panel on your computer and click Devices and Printers. The device should be on that list, right click on it and proceed to properties. Click the Hardware tab, select Nexus 5, then click properties. Update the driver, and point Windows to the folder wherein the extracted the USB driver is. When this is done, there should be a sign listing the device as an Android Composite ADB Interface.
Step 7: Turn the device off, but leave it connected to the computer. Start the handset using the correct key combination to switch to "fastboot" mode. For the Nexus 5, hold the volume up and down buttons, as well as the power button simultaneously.
Step 8: If the lock state says locked, type in "fastboot oem unclock" at the command prompt and press enter. This will erase the data on the device so users are advised to back up important data, settings and other information.
Step 9: With the bootloader unlocked, the Android L firmware can now be installed. Just type "flash-all" and the process will begin.
Step 10: When installation finishes, lock bootloader again for security. Start the device in fastboot mode (like in Step 7), and then type fastboot oem lock.