With Android 4.1 Jelly Bean officially arriving to a number of devices, we've been writing non-stop about Jelly Bean-based ROMs for a number phones and tablets. We're taking a short break from that to bring you the official Android 4.1.1 Jelly Bean build JRO03E update for the Samsung Nexus S (GT-I9020A, GT-I9020T and GT-I9023).

The update is still being gradually rolled out to regions, but for those of you who can't wait, XDA member kibmcz has provided the official update packages, plus a few extras, that you can flash through ClockworkMod Recovery. To make things even better, we'll even show you how to root your newly updated firmware.

In this guide, learn how to upgrade the Nexus S to Android 4.1.1 Jelly Bean and root it.

Warning

• The instructions in this guide are intended for use with the Google Nexus S, model numbers GT-I9020A, GT-I9020T and GT-I9023. Applying these instructions on another device or model may produce undesired outcomes.
• The information in this guide is provided for instructional and educational purposes only. There is no guarantee that these instructions will work under your specific and unique circumstances.
• Use these instructions at your own risk. We shall not hold any responsibility or liability for whatever happens to you or your device arising from your use of the info in this guide.
• Read and understand the whole guide first before actually performing the instructions.

Requirements

• Google Nexus S (GT-I9020A, GT-I9020T, or GT-I9023) with ClockworkMod Recovery installed and an unlocked bootloader.
• Download the following files from the XDA forum thread for the OTA upgrades:
  • Update package (Choose the correct package for your handset model number.)
  • Root package (either stable version or RC2)
  • Face Unlock package (optional)
  • Galaxy Nexus sounds package (optional)
• Backup all personal data on your phone to make sure you have a copy of your personal data (e.g., contacts, SMS, MMS, Internet settings, Wi-Fi passwords, and the like) in case the procedure in this guide erases such data.
  • For backup tips, check our guides on how to sync your data to the cloud and how to create local backups of your mobile data.

Instructions

1. Copy the update ZIP file to your phone's SD card.
2. Turn off your Nexus S.
3. Boot into Recovery Mode by pressing and holding down the Volume Down and Power buttons together. You'll boot into Fastboot mode. Navigate with the Volume buttons to highlight Recovery. Select it using the Power button.
4. Make a NANDroid Backup by selecting Backup and Restore and Backup.
5. Select Wipe data/Factory reset.
6. Select Wipe cache partition.
7. Select Advanced > Wipe Dalvik cache.
8. Select Install ZIP from SD card.  Select Choose ZIP from SD card and locate the update file for your phone's version.
9. [Optional] Once the update file has been installed, you can flash the Face Unlock package, Galaxy Nexus Sounds package, and the rooting package in the same manner as in step 8.
10. Select Go back.
11. Select Reboot system now.

Hooray! You've just given your Samsung Nexus S a boost with delicious Android 4.1.1 Jelly Bean build JRO03E and you've rooted it. What do you think of the update's features? Which feature do you like the best?