Update: seems like there is an easier way http://www.androidcentral.com/verizon-galaxy-nexus-root-toolkit-makes-process-easier-ever
Here are full steps (first 5 are mostly from androidcentral forum post):
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This is a work in progress, and designed with Win 7 in mind, but most of the details will work for all computer OS’s and both the GSM and CDMA model.
Warning. Danger Will Robinson. Ahead, there be dragons.
- This will erase all data on your phone. Everything.
- It also allows you to break anything you want, so be warned.
- It’s easy, but you have to follow instructions. If the instructions are too hard, maybe you shouldn’t be unlocking the bootloader in the first place.
1. Install the Android SDK
- Go to the Android Developer site and download the Windows installer version. Choose the installer version to ensure you get the correct drivers installed.
- Save the SDK to your desktop, right click it and choose to "Run as administrator".
- Accept all the defaults and let the SDK install
2. Set your PATH variable
- Click the Start button, right click Computer and select Properties.
- In the window that opens, on the left, select "Advanced system settings".
- In the next window that opens, near the bottom, select "Environment Variables".
- Another window will open, in the bottom text box select "Path" and click the button labeled "Edit…"
- You’ll see a new dialog where you can enter text. Navigate to the end of the existing text, and enter the following exactly as written:
;C:\Program Files (x86)\Android\android-sdk\platform-tools;C:\Program Files (x86)\Android\android-sdk\tools;C:\Program Files (x86)\Android\android-sdk
- Click "OK" and the small dialog will close. Click "OK" in the Environment Variables window, and it will close, then click "OK" in the System Properties window and it will close. Also close the Control Panel window.
3. Download fastboot.exe for Windows
- Download the zip file attached to this post to get the Windows version of fastboot.exe.
- Extract fastboot.exe from the zip file, and place it in C:\Program Files (x86)\Android\android-sdk\tools\
4. Boot your Galaxy Nexus to fastboot mode
- Shut off the phone.
- Press and hold both Volume Up and Volume Down, then press and hold Power.
- When the phone reboots to fastboot mode. You’ll see an Android robot with his front panel open. Check to see that the text below it starts with "FASTBOOT MODE" in red.
5. Connect to the computer and unlock bootloader
- Now plug the Galaxy Nexus into your computer with the micro USB cable.
- Let any drivers install.
- Once finished, open the Windows command prompt (Start button>All Programs>Accessories) and enter the following:
fastboot oem unlock
- You will see a screen that asks you if you want to unlock the bootloader, explains the pros and cons of unlocking it, and warns you that ALL DATA WILL BE ERASED. It means it.
- Choose Yes to erase all data and unlock the bootloader.
Have fun and try not to break anything
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For me drivers didn’t get installed and windows was not seeing the phone
Here are a few things to try to resolve issue with drivers:
Let’s try with the easiest first: launch SDK Manager from the folder where you installed SDK (need to launch As Admin). Try installing “Google USB Driver Package”. That didn’t work for me
Here are the steps that worked:
Choose “Browse my computer…”
Choose “Let me pick…”