You need to know that Google released Nexus Galaxy – Jelly Bean OTA for Google I/O developers, and as expected, this updated was integrated into a ROM.
The install procedure is pretty simple however the rooting part might be a bit tricky.
Continue to use this tutorial only if you have basic knowledge about the flash procedure and if you device is rooted with CWM Recovery installed.
First, make sure you made back-up copies of your applications and important data. To make it easier you will install ROM Manager from the Google Play Store.
Now, either download the ROM using this link and copy it on a memory card, then select the “Install ROM from SD Card” option from ROM manager or you download and install Jelly Bean using the “Download ROM” option in ROM Manager.
Select the proper options from the list presented before the installation. You can back-up the current ROM and “Wipe Data and Cache” and “Wipe Davlink Cache” are required so you don’t have problems after installation.
That’s everything. You are now free to enjoy the features Android Jelly Bean has to offer!
After you installed the ROM you lost the CWM Recovery and root privileges, but don’t worry.
Download and install Galaxy Nexus Toolkit V7.0. Download CWM-SuperSU V0.92 and copy it on your SD card.
Turn off your phone and start it using fastboot by pressing the volume and power buttons.
Connect your phone to the computer. Start Nexus Galaxy Toolkit and choose the 6 and then the 6 option and install CWM Touch Recovery. After the procedure you can install the zip archive you copied on your SD card using CWM Recovery.
Another important thing to know is if the drivers are not installed on your computer you should use Galaxy Nexus Toolkit to install them.