How to Manually Update GSM Nexus S to Android Jelly Bean (Android 4.1.1)

This tutorial might be the copy of my previous tutorial on how to manually update Nexus S to Android ICS 4.0.4 but with different Android version..the latest Android 4.1.1 a.k.a Jelly Bean. This tutorial is only for GSM version of Nexus S (i9020t/i9023 and i920a). Before doing update, make sure you have access to recovery mode so you can flash the update zip file. I use ClockworkMod to get access to recovery menu.

How to update:

Download the Android Jelly Bean update zip file.
For i9020t/i9023: http://www.mediafire.com/?65j61btjxgvio40
For i9020a: http://www.mediafire.com/?7e1i4kdc7krgi1s
Rename the file to update.zip (optional)
Download SuperUser zip file
Copy the update.zip file and jb_root.zip file into sdcard
Reboot into bootloader end select Recovery
On CWM recovery menu, choose install zip from sdcard then choose zip from sdcard
Choose update.zip file and Yes – Install update.zip on confirmation
Wait until the installation process finish
Back to recovery menu then install the jb_root.zip (from install zip from sdcard menu)
Wait until finish then reboot the phone
After reboot system will update the phone
Wait until finish, then you will be on Android 4.1.1 with root access and super user installed.