Recently, a flurry of Android devices (including Galaxy S3 I9300, Galaxy Tab 2 10.1, Galaxy Tab 7.0, HTC One X and Galaxy S2 I9100) have received the latest Android 4.2.2 Jelly Bean firmware, with due credit to the release of CyanogenMod 10.1 (CM10.1) Nightly ROM from the CyanogenMod Team. The constant flow of custom ROM Jelly Bean releases gains precedence, as Samsung is unlikely to release any further official Jelly Bean updates for its Galaxy series anytime soon.

NOTE: As the firmware is a nightly release, it may harbour a few untested bugs or broken features leading to FC errors, boot loops, isolated app crashes and in the worst case cause a boot failure. If such an issue arises, just reinstall official stock firmware or any other stable custom ROM to fix it.

Key Points to Note

  • CyanogenMod 10.1 Nightly ROM and the instructions given in this guide are applicable to the Galaxy S2 I9100G model only and will not work on any other device. Verify your device's model number by navigating to Settings > About Phone.
  • Verify that the correct USB drivers are installed for the Galaxy S2 on computer (download USB drivers).
  • Back up important data and settings on the phone to avoid unexpected data loss during firmware installation. It is recommended to use either ClockworkMod (CWM) or TWRP recovery for data backup, as it creates a complete image of the existing phone setup.
  • Make sure that the device is rooted with CWM recovery installed.
  • Ensure that USB Debugging mode is enabled on the phone by navigating to Settings > Developer Options (if the device is running Android 4.0 or later) or go to Settings > Applications > Development (if the phone is running Android 2.3 or earlier). Otherwise if the device is running Android 4.2, then do the following steps:
    • Go to Settings > About Phone
    • Scroll down to the bottom and select Build Number.
    • Now, tap the Build Number for seven times to unlock or reveal the hidden Developer Options under Settings. Then enable or select the checkbox for USB Debugging mode under Settings > Developer Options.
  • Verify that the phone has at least 85 percent battery charge to prevent unexpected device shutdown during firmware installation.
  • Do a Dalvik Cache Wipe before continuing from Recovery mode.
  • Samsung KIES will not recognise your device after installing Android 4.2.2 CM10.1 Nightly ROM, as it is a custom release.
  • The instructions provided in this guide are meant for reference purpose only. IBTimes UK will not be held liable if you damage or brick your device during or after firmware installation. Users must proceed at their own risk.

How to Install Android 4.2.2 CyanogenMod 10.1 Nightly Jelly Bean ROM on Galaxy S2 I9100G

Step 1 - Download Android 4.2.2 CM10.1 Nightly Jelly Bean ROM and Google Apps for Galaxy S2 I9100G on your computer.

Step 2 - Connect and mount the phone's USB mass storage on your computer with the USB cable.

Step 3 - Copy the downloaded Android 4.2.2 CM10.1 Nightly ROM and Google Apps zip files to the root folder of your phone's SD card.

Step 4 - Power off your phone and disconnect its USB cable from computer.

Step 5 - Boot the phone into Recovery mode by pressing and holding Volume Up, Menu and Power button together until the phone reboots into CWM recovery.

Step 6 - In CWM recovery, do a full data wipe first. Then navigate to Flash zip from SD card option and hit Power button to select it.

Step 7 - Tap the Power button again and click Choose zip from SD card.

Step 8 - Use volume keys to navigate to the Android 4.2.2 ROM zip file that you copied earlier to your phone's SD card and select it by tapping the Power button. Confirm the ROM installation on next screen and the installation process will begin.

NOTE: Repeat this step for installing Google Apps as well.

Step 9 - Once both the ROM and Google Apps are installed, hit Go Back and reboot the phone by tapping Reboot System Now in the recovery menu. The phone will reboot and the first boot may take about 5 minutes to complete. So, do not interrupt the process.

Your Galaxy S2 I9100G is now running Android 4.2.2 CM10.1 Nightly Jelly Bean ROM. Go to Settings > About phone to verify the firmware version installed.

[Source: Team Android]