It will take some times to reach the Android 5.1.1 OTA (over the air) update notification on your Nexus 4 and Nexus 5. However, if you are excited to try the new Android 5.1.1 Lollipop on your phone, you can install the update manually. Read on to know how to install the Android 5.1.1 update manually on Nexus 4 and Nexus 5.

Before you start installing the Android 5.1.1 update on Nexus 4 & Nexus 5, make sure that your Nexus 4 is running on the stock Android 5.1.0 (LMY47O) and Nexus 5 is running on Android 5.1.0 (LMY47I). Note: This process will wipe your phone completely, so backup any important data on your phone.

How to Install Android 5.1.1 Update on Nexus 4 & Nexus 5

  1. Install ADB and Fastboot driver on your computer (You can use minimal adb and fastboot [HERE] for this purpose)
  2. Download Android 5.1.1 Lollipop factory image for Nexus 4 (LMY47V) [HERE] and for Nexus 5 (LMY48B) [HERE] and unzip the .tar file. Move the unzipped files to the same folder as the Minimal ADB and Fastboot installed on your computer (usually it will be C: – Program Files (x86) – Minimal ADB and Fastboot).
  3. Enable “USB Debugging” on your device from Developer options menu.
  4. Now, power off your Nexus 5 or Nexus 4 and enter into “fastboot” mode by holding down the Volume up + Volume down + Power buttons together. Then, connect your phone to your computer via a USB cable
  5. Now go to the Minimal ADB and Fastboot folder and open a command window there (shift key + right click and select open command window here option).
  6. If the LOCK STATE says locked, then type: fastboot oem unlock at the command prompt, and press Enter. On your phone, choose “Yes” (use volume key) and confirm it by pressing the Power button. Note: This will ERASE your device, so make sure you have backed everything up first.
  7. With the bootloader unlocked, you can install the Android 5.1.1 firmware. To do that, go to the Minimal ADB and Fastboot folder (where you have saved the unzipped factory image) and execute the flash-all script. 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”. Wait for the process to complete. The phone will reboot automatically. Note: Once you installed the new firmware, you should lock the bootloader again for security. For that, boot your device into fastboot mode, and then issue the command: fastboot oem lock (source – Google)