Hi folks. In this guide, we'll be unlocking the bootloader and rooting the Google Nexus 4. This will allow us to install custom ROMs which offer a different Android experience, install root-only apps that provide more advanced functionality, as well as perform easier backups of our phone.
As with most Nexus devices, unlocking the bootloader and rooting the phone is actually quite easy with the correct tools. Let's get started!
1. Download and install Nexus Root Toolkit 1.6.1
The first order of business is to download the Nexus Root Toolkit, which was developed by Wug on the XDA Developers forums. The most recent version as of this writing is version 1.6.1, so be sure to download at least that version. You can always find the most recent version here:
Scroll down to the section that says 'Download', and download the file. Once downloaded, install it to the directory that it suggests.
When it's finished, launch the application - this is what we'll be using to accomplish our goals today. Select the Nexus 4 as your device, and be sure to select which version of Android it is running as well. If you're on the most up to date version, you should select version 4.2.1 build number JOP40D. You can always check this in 'About phone' under 'Settings' if you're not sure.
2. Enable USB Debugging
First thing's first - we need to enable USB debugging. On the Nexus 4, go to Settings. You can do this by pulling down the notification menu with two fingers then clicking on Settings in the upper right corner, or running the Settings app from the app drawer.
Scroll down to the bottom of the Settings list. If you don't already have Developer options listed just above About phone, we'll need to make that section appear first. To do that, click on About phone, then scroll down to the bottom of the list. Now, tap on Build number about ten times - just keep tapping away until it tells you that you've become a developer.
Now that you can access it, go into the developer options. Enable these by pressing the toggle at the top and accepting the 'Allow development settings?' dialog box. Under the debugging section, click the check box that says 'USB Debugging'. Accept the dialog that appears, and USB debugging should be enabled.
Now, when you connect your phone to a PC via USB you should get a cloud-shaped symbol in the toolbar that states USB debugging is enabled.
3. Install the correct ADB and Fastboot drivers
Before we can really get started, we need to install the correct drivers for the Nexus 4. This can be easy or moderately challenging depending on what drivers you've got lying around on your system already, but if you keep working at it you should find it more than achievable.
To start off, you'll need to uninstall all previous drivers. To do this, click 'Full Drive Installation Guide - Automatic and Manual' in the Nexus Root Toolkit.
Then, follow the instructions to remove all previous drivers:
- Plug in your Nexus 4 via the original USB cable into your PC with USB debugging enabled.
- Use the Device Manager to uninstall the Nexus 4's drivers, which should appear as ADB device or similar (via the Launch Device Manager button at the bottom of the window)
- Unplug the Nexus 4
- Use USBDeview (using the Launch USBDeview button at the bottom of the window) to uninstall any other USB drivers. This is fairly quick and painless, and don't worry about uninstalling something important - most other devices will easily reinstall themselves if necessary. Just select anything related to Android ADB, Samsung or Google, then right click and hit 'uninstall selected devices'.
- Reboot your PC.
Once you've uninstalled the drivers and rebooted, you can install the proper ones. Move onto Step 2 (via the tab at the top of the Full Driver Configuration Guide window). There are three different driver installation procedures here; do whichever is recommended.
I'm using Windows 8 and was recommended to use method #3, so I'll briefly let you know what I had to do.
The first thing was to reboot into a mode with no driver security, so that the drivers could be installed unsigned. To do this, I went into the Charms Menu, then Settings, then General, then Advanced Setup, then Restart Now. The computer restarted and I was given an option to 'disable driver signature enforcement', so I pressed the relevant button and booted into Windows again.
From there, I plugged in the Nexus 4 and relaunched the Nexus Root Toolkit program, went into the Full Driver Configuration Guide, Step 2, Raw Drivers, then hit 'OK'. Then it was just a case of following the step-by-step instructions to open device manager and upgrade the ADB device drivers with ones provided by the Nexus Root Toolkit, then rebooting the Nexus 4 into Fastboot mode and installing the correct drivers here as well.
Once you've completed Step 2, move onto the third tab. Click the Full Driver Test button and you should receive a success message. If so, then you've got things properly configured and you can move onto the next step.
If not, then something's gone wrong - make sure your device is plugged in via the original cable into a USB 2.0 port, has USB Debugging enabled and then try again. You might want to try a different method of driver installation, too. Keep going until you get it right!
4. Make a backup
Unfortunately, to unlock your Nexus 4 we'll need to wipe it clean. This means backing up your data before we begin is a great idea; if your Nexus 4 is fresh then you can move onto the next step.
If you've already used your Nexus 4, chances are that you'll have some things on there that you'd like to save. I use Dropbox to back up my images as they are taken and I remember the layout of my home screens by taking screenshots of each one (VolumeDown + Lock).
The Nexus Root Toolkit can also help you back up some data - apps, some app data, SMS, call logs, contacts, your APN settings and indeed the entire virtual SDcard which has your media on it like photos.
Let's start with one that'll save you a lot of time - backing up your apps. Just click on Backup in the Nexus Root Toolkit, then choose the 'Create Android Backup File' option. You shouldn't check either of the boxes below that button.
You'll get a window of text - read it all, it's important. Turn your phone to Aeroplane mode as suggested, then click OK. A window will pop up asking you to choose a file name and location for your backup file. Just accept the defaults and continue.
Again, you'll get a window of text - as always, read it! You'll want to ensure that your phone is unlocked and in your hand ready to go. Click OK once more, then on your phone agree to make a backup. You don't need to encrypt the file with a password if you don't want to.
Once accepted, it'll take some time for the backup to complete depending on many applications you have. Just let it proceed to completion. Once finished, you can either back up other things by following the Nexus Root Toolkit instructions or move onto the next step if you're confident nothing of importance hasn't been backed up.
5. Unlock your bootloader
Now comes the fun part. From the main Nexus Root Toolkit window, select Unlock. Your phone will automatically reboot into bootloader mode and trigger the OEM unlock option. Use volume keys to confirm the unlock, then confirm your 'Yes' selection by pressing the lock button.
The phone will reboot and will now be unlocked - but it will also be wiped. Complete first time setup again; go ahead and install apps / updates if you like. Remember to go back into developer options and re-enable USB debugging!
6. Root and flash custom recovery
With the bootloader unlocked and USB debugging enabled once more, hit that Root button. I'd also recommend selecting the option below that will flash a custom recovery for you. This'll make installing modifications and new ROMs easier in the future.
You may need to download some files; each time agree and the files will be downloaded for you. The rooting process will then proceed automatically. Your phone will reboot and display some odd screens, but just keep it connected via USB and wait until the Nexus Root Toolkit prompts you to open the SuperSU app.
Update SuperSU via Google Play (it should auto-update), then launch the app. You'll be prompted to update the binaries once in the app - accept this. Once it's done updating, close the app.
Then, launch the BusyBox installer app. This should prompt it to ask for superuser permissions - grant these, and then go ahead and do a smart install. You'll have to wait a minute or two for this to be prepared, then click 'Install' and then 'Smart install.'
Once that's complete, your phone is rooted and ready to go! There's just one thing left...
7. Restore your data
Now you can restore your apps and data if you backed them up via the 'Backup' command earlier. From the main Nexus Root Toolkit window, hit Restore and choose your .ab file to begin the process. Wait until it's done, then it should reboot and you should have your old apps and data back.
If you backed up your text messages, call logs and/or SD card then just follow the relevant instructions in the Nexus Root Toolkit to restore them too.
8. Success!
Congratulations - you've backed up, unlocked, rooted and restored your phone! Good work, and I hope you found the process educational. If you have any queries, ask below and I'll try to help.