[Device Reviews and Information] tinpanalley:
I've done this for my phone and my wife's phone and I've done it twice. If following what I'll tell you doesn't work, I won't be able to help further.

You DO basically need to follow each and every step but there is a point where, regardless of what people may say, there is an important step missing that I could only get when [MENTION=4579290]Froid[/MENTION] helped me.

- To make sure you do what I did, you have to use Minimal ADB and Fastboot. And EVERY time you're asked to use adb, you have to use the "cmd-here" executable in the install folder of Minimal ADB. I don't know why it doesn't work in Powershell or other methods, maybe it's just my computer, but it doesn't. Just use "cmd-here" to be safe.

- Secondly, assuming you're on Lollipop and not MM and just want to root, I'd get your phone to format the microsd card. Then when it's done, put the superuser zip on the microsd card.

- Finally, get the recovery you want to use, TWRP is my choice. Copy it into the Minimal ADB folder and rename it "TWRP" or something else easy to type in. Then when you go to flash it over

Once that's done, just follow along the steps below...​

1) Unlock Bootloader (nothing different here from the original post)

Power on the phone and skip through all of the setup options

Go to Settings -> About device

Tap Build number five times to enable Developer options

Go to Settings -> Developer options

Enable OEM unlocking

Enable USB debugging

Plug the phone in to your PC and authorize it

Open a Command Prompt

Type adb reboot-bootloader

The phone should reboot and in a very tiny font at the bottom you should see => FASTBOOT mode

Type fastboot devices to verify that your PC sees it correctly

Type fastboot oem unlock

Press Volume Up to say Yes and wait for this to finish

Type fastboot getvar all and look for (bootloader) unlocked: yes

Type fastboot reboot

You should see your phone reboot a couple times as it erases the phone

2) Install Custom Recovery (here we'll adjust the end...)

Power on the phone

You can configure your phone now or just skip through all of the setup options and do that later

Go to Settings -> About device

Tap Build number five times to enable Developer options

Go to Settings -> Developer options

Enable OEM unlocking

Enable USB debugging

Plug the phone in to your PC and authorize it

Open a Command Prompt to wherever you extracted the .img file

Type adb reboot-bootloader

The phone should reboot and in a very tiny font at the bottom you should see => FASTBOOT mode

Type fastboot devices to verify that your PC sees it correctly

For CWM or TWRP type fastboot flash recovery TWRP.img (or whatever you renamed it)

Type fastboot rebootHere's where we're going to modify things. This is where you'll follow [MENTION=4579290]Froid[/MENTION]'s directions instead.

Type fastboot reboot, don't press enter, hold down the power and volume up and volume down all at the same time and THEN press enter on the keyboard when you've got the buttons held down. Hold them down until you get another screen that asks "if you want recovery press volume up". Go ahead and do that. This should boot to TWRP."

The reason this button combo is necessary is because without it, the phone will wipe itself when you reboot on "fastboot reboot" and go to the default Android recovery menu. The key combo ensure it doesn't wipe and goes to the TWRP recovery you just flashed over.

Now having put the Superuser zip file on the microsd card as I mentioned before, you don't have to worry about the fact that the phone has wiped itself clean because your sdcard will still have the zip file. From within TWRP you can install a zip and go select the superuser zip file on your microsd card.

That should basically take care of it. Once you reboot after that process, you'll be rooted.