In case you didn’t know, Motorola has already made it official that they have begun Android 5.1 soak test for the 2nd gen Moto X. But guess what, you can test it out on your own Moto X without necessarily joining the soak test as the Android 5.1 update is available for your download, and can be flashed via recovery using the ADB sideload command. If you’re new to this, we’ll help you out, just look below.

How to update Moto X 2014 (2nd Gen) to official Android 5.1 Lollipop

Warning: We won’t be held responsible if anything goes wrong. You only are responsible if anything happens to you or your device.

Downloads:
Procedure:
  1. Make sure you are on official Motorola firmware, and don’t have any custom recovery installed. Though, TWRP’s ADB sideload might work, but avoid that.
  2. Download both the update file and ADB file from the download section above. Extract all contents of ADB files.
  3. Create a folder, name it as motox51soak. Transfer all contents of ADB file and the update file to this folder, motox51soak.
  4. On Moto X, enable USB debugging:
    1. Go to settings, about phone.
    2. Tap on build no. 7 times to unlock ‘developer options’ in settings.
    3. Come back to settings, and go into developer options.
    4. Find USB debugging and select it. Accept warning. Make sure it’s selected. Work done, come back to homescreen.
  5. Let’s test ADB, whether it’s working alright or not:
    1. After USB debugging is enabled, connect Moto X to computer using USB cable.
    2. On PC, go to folder motox51soak, find empty white space inside the folder and click using mouse’s left button. This is to make sure that no item in the folder is selected buy default.
    3. Now, hold Shift key on keyboard, and then click using right button of mouse. It will get you pop-up of options, select ‘open command prompt here’.
    4. Command prompt window will open up, with location of your folder, motox51soak.
    5. Type adb devices and hit enter key.
    6. If you get a serial no. with device written right to it, ADB is working. If you get waiting for device, then it means it’s not working fine. You need to install drivers, restart PC, and then do step 4 again. Don’t close this window, btw. We’ll need it in step 7.
  6. Once you’ve got ADB working, you’re set to apply the update from recovery. Entering recovery is tricky, but here’s how it’s done.
    1. Power off your Moto X.
    2. Enter bootloader mode: hold volume up, volume down and power button (all three together) for around 5 seconds and then let go. You should see boot menu, with options under the title ‘Boot Mode Selection Menu’.
    3. Important! How to use this screen. Use only volume down to browse between options. Don’t use volume up for this. Volume up selects the option, so press it only when you’ve reached desired option!
    4. Move the selection to Recovery using volume down key. Keep pressing to loop over if you miss the recovery option, it will be back on top option when bottom is reached and you press volume down. So, use only volume down button and reach the recovery option.
    5. Press volume up button to select recovery and this will boot you into a new screen with Android and red triangle with exclamation mark.
    6. Hold volume up and down together for 5 seconds and then press power button to get into recovery mode. Now, you can use both volume up and down to move between option, while power button would select the option.
  7. So, move to ‘apply update from ADB’ option, and then select it using power button.
  8. On the command prompt, from step 4, type adb sideload victara_android_5.1_ota.zip and then hit enter key.
  9. The Android 5.1 soak test update file will be transferred to your Moto X and then installed. Good luck!
  10. Once done, select the ‘reboot system now’ option to restart the phone. You should have Android 5.1 running on your Moto X ’14.

Let us know if you need any, any help regarding this.