Thanks to XDA forum senior member CypherPotato, this guide has successfully tested on device XR1900-5 (Android 8.0), XT1900-6 (Android 8.1), XT1900-7 (Android 8.0) and XT1900-4. It will not work on XT1900-2. You do not require unlocked bootloader on the device to install the Android 9 Pie OTA update. Requirements: – An SD card with at least 2GB storage space free – At least 80% battery charge remaining on the phone – ADB and Fastboot driver setup on the PC – Latest Motorola driver installed on your PC Obviously, this guide is NOT for beginners. It is recommended for technically talented users only. We advise you to follow this guide only if you know what you are doing. Before applying the Pie OTA update, you should first update your device to latest version. If your device is running on Android 8.0 Oreo, download this file and install it using this guide. If your device is running on Android 8.1 Oreo, download this file and install it using the same method. Note: If your current version number is higher than the downloaded version, do NOT flash the above given files. It will break your device. Follow the instruction at your own risk. We will not be liable if any damage occurs to your device and/or its components. Backup all data you have on the phone before proceeding.

Installation Instruction

  1. Download Android Pie OTA update [here]/[source] and save on your phone’s storage.
  2. Turn off Moto X4 and boot in to Recovery mode

Press Power+Volume Down key to boot into Fastboot mode When you see “No command“, press Power button and then press Volume Up button

  1. In Recovery, select “Apply update from SD card” and select the update package.
  2. The update process will start. It will take some times to complete. Once done, your phone will reboot. Note: a) If you come across any issue after installing the update, do a factory reset. (Settings -> System -> Advanced -> Reset options -> Factory reset) b) If the phone stuck on boot screen, soft reset it by holding Power button for 15 seconds. [source – xda]