Android Nougat brings features such as multi-window, redesigned quick settings, improved notifications, better battery management, Direct Reply and more. To check the OTA update, from the Home screen tap All apps > Settings > About > Software updates > Check now > Download. Once the download is complete, tap the System update to begin the upgrade process.

Now, if you are outside of Wi-Fi coverage, or the update is not found due to some unknown reasons, you can perform a manual system update via USB connection to a PC. However, you need to download the massive (1.8GB) firmware file (RUU.exe) to your PC to install manually. Note: The below update process will delete all information from your phone, so back up data you have on the phone before proceeding.

How to Update One A9 to Nougat and Sense 8 Manually Using RUU File

First Method

  1. Download HTC Sync Manager from here and install it on your PC.
  2. Download HTC One A9 Nougat RRU update file (1.8GB) from here or here to your PC.
  3. Connect your phone to your PC. Once the device is properly recognized, navigate to Nougat RRU update exe file and double-click on the exe file. It will launch the system update wizard.
  4. Follow all of the system update wizard instructions shown on your PC. Once done, click Finish in the wizard and your phone will reboot. Enjoy! [If the above method does not worked for you, then try the below method] Second Method
  5. Turn off the phone, press Volume Down button and press Power button to turn on the phone.
  6. It will boot your device in to ‘Download’ mode
  7. Connect the device to the PC and start the ROM update process again
  8. Once the device reboots, set up and enjoy. [To exit download mode manually, use the volume keys to navigate to reboot and press the POWER button to select it] After the initial setup, open Play Store, tap the Menu icon, then select My apps and ensure all installed apps are updated. Leave your views in the comment section below (Source – HTC)