Android 5.0 Lollipop was made official a few days ago. As is the norm, Nexus devices are the first ones to receive the official update. Google has started to roll out the OTA update for the Nexus devices. Not all the devices have received the update yet. Google usually performs this operation in batches. If you are feeling too impatient, then you can install Android 5.0 on Nexus 5, using Google uploaded factory image. Follow the guide given below.

Disclaimer: Follow the instructions at your own risk. The writer cannot be held responsible for any bricked or unusable devices. Even though the chances of your device getting bricked are negligible, the owner of the device must take full responsibility of it!

Pre-requisites and Backing up your Nexus 5:

• Make a Backup of the SMSs, Call logs and Contacts using the Super Backup App
• Make a Backup of the data
• Make sure developer options is unlocked
• Enable USB debugging on your device
• Make sure the device has at least 60% charging
• Backup WhatsApp messages on Android and Email

Requirements:

• Nexus 5 drivers installed on the computer
• Android SDK installed on the computer
• ADB and Fastboot installed on the computer
• Nexus 5 factory image

Steps:

1. Make sure ADB and fastboot files are placed in the same folder.
2. Download the Nexus 5 factory image and extract it to a convenient location.
3. Connect the phone to the PC.
4. Power off your phone and boot it into Fastboot/Bootloader mode by pressing and holding the Volume Up, Volume Down and Power buttons until the Fastboot menu and START icon appear on the screen.
5. Go to the hammerhead-LRX21O folder obtained by extracting the files in step 2. Copy and paste all the files to the Fastboot directory.
6. Using factory image files in your Fastboot directory, run the following commands depending on the OS installed on computer:
   On Windows: Run the file “flash-all.bat”.
   On Mac: Run the file “flash-all.sh” using Terminal.
   On Linux: Run the file “flash-all.sh”.
7. Wait for the process to complete. The phone will reboot automatically.