Just recently, the OTA update for Android 4.1.2 Jelly Bean build JZO54K for some of the Nexus devices started rolling out to some regions. Apparently, there are still some owners who have reportedly received nothing and have been tapping on their devices' System Update option in hopes of receiving the update. Some have decided to wait in vain and some have decided to manually upgrade their devices.

Android 4.1.2 build JZO54K provides more than a newer version of Jelly Bean. This update allows users to bid bye-bye to expanding and collapsing notifications with two-finger gestures. With this update, one-finger gestures are enough to expand notifications by tapping and dragging notifications downwards and collapse notifications by tapping and dragging notifications upwards.

If you have with you a Google Nexus S (GT-I9020, GT-I9020T, or GT-I9023) and opted to go for updating your phone manually, you are in luck. Today, you can happily go to bed knowing that your Nexus S had been updated to the latest build.

This update will also restore your phone to stock firmware if you want to revert from a custom ROM. For users of the Sprint variant, the Nexus S 4G SPH-D720, you may have to wait a bit more for developers to release your phone's factory image that will allow you to update your phone to Android 4.1.2.

This guide shows you how to flash stock Android 4.1.2 Jelly Bean build JZO54K for the Nexus S manually. Official Google-provided factory images are used.

Warning

• The instructions in this guide are intended for use with the Google Nexus S, model number GT-I9020, GT-I9020T, or 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-I9020, GT-I9020T or GT-I9023
• Your phone's USB cable
• A GNU/Linux Machine with Android SDK (Software Development Kit) installed and with the platform-tools package installed
  • For pointers, check out our guide on how to install the Android Software Development Kit to your PC.
• Configured USB access for ADB to properly interact with the phone by setting udev rules.
  • For help, refer to Android Open Source Project’s guide on configuring USB access.
• Download the Android 4.1.2 Jelly Bean Build JZO54K for the Google Nexus S (soju-jzo54k-factory-36602333.tgz, md5sum: 788233dca5954532acda63039f814b4d)
• See to it that your phone's battery is charged to 75% or more to avoid interruptions during the process.
• Backup all personal data on your device 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. Unpack the Android 4.1.2 Jelly Bean archive. You can unpack the file by right-clicking and selecting “Extract here…”. You should be able to get a folder named soju-jzo54k.
2. Switch off your phone and boot into Fastboot Mode. To do this, press and hold the Volume Up and Power buttons until the phone boots into Fastboot Mode.
3. Connect your phone to the PC using the USB cable.
   • NOTE: Make sure that fastboot can communicate with your phone. To check, type in fastboot devices on your PC's command prompt. Running these commands should allow you to see your phone's serial number.
4. Unlock your phone's bootloader by typing in fastboot oem unlock at the terminal.  On your phone, confirm that you want to unlock the bootloader.
5. After unlocking your phone's bootloader, reboot the bootloader by typing entering fastboot reboot-bootloader at the terminal.
6. Once the bootloader reboots, change directory to the soju-jzo54k folder in your computer. Run the flash-all.sh script by entering the command below:
   • ./flash-all.sh
7. For security reasons, relock the bootloader after flashing the firmware. Reboot back to Bootloader Mode and enter the command fastboot oem lock at the terminal to relock the bootloader.
8. Reboot your phone to Normal Mode.

Great job! You have successfully upgraded your Google Nexus S GT-I9020, GT-I9020T, and GT-I9023 to Android 4.1.2 Jelly Bean build JZO54K manually. What are some of the noticeable improvements? Let us know what you have observed after applying the update by commenting below.