I know there are already a few root guides out there for this phone, but I found that they weren't very detailed. This guide is thorough and explains each and every step in a noob-proof manner.

Basic tasks that I may refer to throughout this guide:
Open command prompt - Press Window Key + R, type in "cmd" (without the quotes), and hit enter.
Enter fastboot mode- Turn the phone off. Hold volume up + power until the "fastboot" screen appears.


ADB & Fastboot Installation:
Download the full Android SDK here (scroll to the bottom of the page>DOWNLOAD FOR OTHER PLATFORMS>SDK Tools Only) or get a slimmed version containing only the essential components here
Extract the zip and place the android-sdk-windows folder on your desktop.
**If you chose to download the slimmed sdk skip to step 5**
Only if you downloaded the full sdk: Go into the android-sdk-windows folder and run SDK Manager.exe. Install the following packages (there are a total of 4 packages):
- Tools > Android SDK Tools, Android SDK Platform-tools
- Extras > Android Support Library, Google USB Driver

Only if you downloaded the full sdk: Go back into the android-sdk-windows directory, and you should see a new folder named platform-tools. If you don't see this new folder, repeat the step above.
To confirm that it is indeed working, open a command prompt window and enter the following commands:
Code:
cd Desktop/android-sdk-windows/platform-tools
adb version
If it displays "Android Debug Bridge version x.x.xx" it is working. If it is gives an error saying that adb is not a recognized command, it has not been successful. Carefully repeat the steps above if this is the case. Close the command prompt window when you are done.
Show File Extensions - Open a command prompt window and run "Control folders" (without the quotes). Go to the View tab and uncheck the "Hide extensions for known file types" option. This will help avoid confusion when renaming files.
Battery - Ensure that your phone has at least 60% battery remaining, and that your PC is plugged in and wont shut down spontaneously during the process. The procedure doesn't take very long (5-15 minutes), but its best to have enough charge in case something goes wrong.
Backup (Optional) - Unlocking the bootloader will completely wipe all data from the device. This includes apps, settings and even the contents of the internal sdcard (pictures, music, etc.). Copy all important files off the phone onto a PC or upload them to a cloud.
Driver Installation - Download and install the Universal ADB Driver. Alternatively, use this method.
Downloads
Download a custom recovery and the SuperSU zip below. Place both files (recovery image and root zip) in the platform-tools folder located on your desktop within the android-sdk-windows folder.

Custom Recovery:
TeamWin Recovery Project (TWRP)

Root:
SuperSU


Information
Rooting this device is actually quite a simple and easy process. Before you begin, it is recommended that you at least try to understand what each part of the process will do. Although this guide will elongate each step in order to show all of the details, the method used can be broken up into 3 main steps: Unlocking the Bootloader, Installing a Custom Recovery and finally Rooting. Each new step relies on the previous step to have been completed, and a basic summary of each part is:

Unlocking Bootloader: Opens the door to the internal memory of the device to be written on to. This allows you to flash images onto the main partitions of the phone.
Installing a Custom Recovery: A custom recovery is flashed onto the recovery partition of the device and overwrites the stock recovery that exists by default. Custom recoveries bring lots of functionality and give you the ability to perform wipes, install flashable zips, create full backups of your NAND (Nandroid backup), and various other features. An unlocked bootloader is needed to install a custom recovery.
Rooting: You can gain root by either flashing via recovery a pre-rooted custom rom, or flashing a zip containing the SuperSU binaries. A custom recovery is necessary to do this.

After completing these steps your phone will be rooted, the phone will have a custom recovery installed, and the phones bootloader will be unlocked. This, in my opinion, is the most practical and beneficial method for rooting your phone. It gives you some basic adb/fastboot knowledge, and should hopefully help you have a decent understanding of what is going on. Also this method will work regardless of what android version your phone has.

If you are confused by anything in this guide, I would highly suggest getting it clarified being before moving on. Ask your question in this thread and I or someone else will likely answer. Also I'd suggest that you read over the whole thread a few times before actually doing anything to the phone.

Understand? Good...lets begin





1. Unlocking Bootloader
Turn the phone off. Then boot it into fastboot mode by holding volume up + power. The phone will display "fastboot" text indicating that it has successfully entered fastboot mode.

Plug the phone into your PC, then open a command prompt window and type:
Code:
cd Desktop/android-sdk-windows/platform-tools
Code:
fastboot devices
This command will list the connected devices. If your phones serial number shows up you are good to go and may continue. If the phone is NOT listed this indicates that your drivers are not installed correctly. In order for you to continue you must fix your drivers so that your phone is listed under fastboot devices.

If the phone has been recognized by the command above, proceed to unlocking the bootloader with the following command:
Remember that this step will wipe EVERYTHING off the phone
Code:
fastboot oem unlock
After the above command has finished excuting, run the following
Code:
fastboot reboot
The phone will reboot. Wait until the phone has fully booted up into android, then adjust the following settings on the phone:

USB Debugging - On your phone go to Settings > About phone > Tap on Build number 7 times. This will enable Developer options. Now go back to Settings > Developer options > Enable USB debugging
Disable CM Recovery Protection - On your phone go to Settings > Developer options. Then disable the 'Update recovery with system updates' option.

Close the command prompt window and proceed onto the next section of the guide.


2. Installing a Custom Recovery
Turn the phone off. Then boot it into fastboot mode by holding volume up + power.

Rename the recovery file that you downloaded above to recovery.img. *Make sure that you rename it to recovery.img NOT recovery.img.img* Remember that this file should be placed in the platform-tools folder inside of the android-sdk-windows folder on your desktop.

Open a new command prompt and run the following commands:
Code:
cd Desktop/android-sdk-windows/platform-tools
Code:
fastboot flash recovery recovery.img
Once the flash has completed type the following command to reboot the phone:
Code:
fastboot reboot
After the phone has booted back up, turn it off. Now to enter your newly installed custom recovery, hold volume down + power. The phone should boot into recovery mode. Now that you have a custom recovery, you may continue to the final step.
Close the command prompt window.


3. Rooting
Now that your phone has an unlocked bootloader and a custom recovery installed you have a two options to gain root (Pick one or the other. You don't need to do both)

Option A) Flash SuperSU binaries which will give you root with the stock ROM
Confirm that you have downloaded the SuperSU zip from the downloads section above and that it is located in the platform-tools folder inside of the android-sdk-windows folder on your desktop.
Turn the phone off then boot into recovery mode by holding volume down + power. Leave the phone at the main screen of the custom recovery for now.
Open a command prompt window and run the following commands:
Code:
cd Desktop/android-sdk-windows/platform-tools
Code:
adb push UPDATE-SuperSU-vX.XX.zip /sdcard/
This will copy the SuperSU zip onto your phone. Once the command has completed continue.

Instructions for TeamWin Recovery Project (TWRP):
Install > browse to SuperSU zip and select the it
Swipe to confirm the installation. Then reboot.


If u follow these steps correctly u wount have any problem. My OPO is already running on Lollipop courtesy of BLISSPOP

Excellent guide for the technically savvy, but Wugfresh bacon root tool kit is the easiest bro, it does it all for you.. just download on PC and click away, Check it out just in case you might wanna flash back to stock. What's the battery like on bliss pop, better than stock? I have heard a lot of good things about that ROM..

http://www.wugfresh.com/brt/

Yeah right u can use that took kit.

The ROM makes sense, the ba3 last longer on it