Recently Google released the new official Android 4.4.3 for the Nexus 5 Android smartphone. The update comes with some fixes and new features. You can updates your nexus 5 via the OTA method. Go to the setting of your phone and update the device. If you have the rooted device and using some custom ROM on your device than you can’t get this update via OTA method. To update your device you have to install the Android 4.4.3 manually on your nexus 5. Or if you can’t wait for the OTA update on your country and then you can also follow this guide to Install Android 4.4.3 on Nexus 5 Mobile.
The steps below will also work if you have a custom ROM, kernel or have root access on your Nexus device. However, keep in mind this will erase all the files from your phone, so do take the backup of your phone. After that follow the below mention guide to update your android.
Install Android 4.4.3 on Nexus 5
1). Download the Android 4.4.3 factory image for your Nexus 5 here [hammerhead-ktu84m-factory-53ff95bf.tgz.tar] and save the folder on your desktop.
2). Extract the file on your desktop and you will see the new file hammerhead-ktu84m-factory-53ff95bf.tgz in the extracted folder. Extract this file again and you will see the new folder “hammerhead-ktu84m”.
3). Now download the required ADB/Fastboot files to flash the update on your device, which can be downloaded from below:
And extract the folder on your desktop.
4). Now move the Android 4.4.3 image files (Same files that you extracted on the Step 2 “hammerhead-ktu84m”) on the ADB folder.
5). You will now need to reboot your Nexus into Bootloader mode. To do this, switch off the device, and then simultaneously press the Volume up + Volume down + Power button. This should get you into Bootloader mode.
6). Once you are on boot-loader mode, connect your phone to the PC with USB cable.
7). Now open the ADB folder on your desktop, click on the flash-all.bat if you’re on Windows PC or flash-all.sh if you’re on Linux, now the flashing starts.
The flashing process will take some time to complete, once it will finished your phone will reboot automatically. The first boot process will take some time as the OS needs to recreate the cache files for all your installed apps and games.