Samsung is still not providing any details on when the Android 4.1 update is expected to arrive for the Samsung Galaxy S2 GT-I9100G. While we wait for Samsung’s update, custom ROM developers, such as those for CyanogenMod and AOKP, have brought out custom ROMs for avid fans like you. They've developed custom ROMs based on Android 4.1.1 Jelly Bean and added their own twists and improvements to these custom ROMs.

CyanogenMod and AOKP have been brought together to give rise to a custom of ROM called Vanilla RootBOX. With the two best custom ROMs brought together, Vanilla RootBOX Jelly Bean 4.1.1 custom ROM acquired the best customization features of CyanogenMod 10 (CM10) and AOKP ROMs had to offer. While Vanilla RootBOX has all the luxury of inheriting great features from CM10 and AOKP, it also has its own issues.

Current features that are not working:

• Google Ears
• Rom Control – Missing features (NavBar doesn't work)
• Long press to search
• A2DP, also known as Music over Bluetooth (Untested on I9100G) (Bluetooth calls and file transfers work!)
• Mounting points are changed in JB! (/sdcard /extSdCard)
• No option to swap Internal/External
• Only MTP connection (No UMS for now!)
• DPI can only be changed by manually editing build.prop

Below are the working features that Vanilla RootBOX has as of the moment:

• Based on JB 4.1.1(Built from RootBOX Sources – RootBox Sources)
• Kernels: HorsePower 2.0.6
• Launchers: Nova, Apex & Default Launcher
• File Manager: ES File Explorer & Solid Explorer Beta 2
• Music Player: Google Play Music, Sony Walkman Music Player & Apollo Music Player
• Music Enhancement: DSP Manager
• Google Apps – Jelly Bean 4.1.1 (20120724)
• Camera: AOKP + cherry picked CM9 features
• Tweaked build.prop
• Modified host file (Block ads)
• Init.d Fix applied

Vanilla RootBOX also acquired the best features Jelly Bean has to offer, like smoother interface, advanced voice recognition, improved and even more useful notifications, among others. However, please take note that Vanilla RootBOX is in its early phase, so bugs and issues may arise. The ROM is not recommended for day-to-day use but can provide you a sneak preview of Android 4.1.1 Jelly Bean on your Galaxy S2 I9100G.

In this guide, learn how to upgrade the Galaxy S2 I9100G to Android 4.1.1 Jelly Bean via Vanilla RootBOX custom ROM.

Warning

• The instructions in this guide are intended for use with the Samsung Galaxy S2, model number GT-I9100G. 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

• A rooted Samsung Galaxy S2 GT-I9100G with ClockworkMod Recovery installed. Check this guide if you need help:
  • Samsung Galaxy S2 GT-I9100G: Rooting ICS firmware version XXLPQ and installing ClockworkMod Recovery
• Download the Vanilla RootBOX v2.1 JellyBean ROM (RootBOX_JB_2.1_I9100G.zip, md5sum: 128466c6b503f3876c09bfa0c82f1c25)
  • Direct Link
  • Mirror Link
• 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 Vanilla RootBOX ROM ZIP file to your phone's internal SD card.
2. Turn off your Samsung Galaxy S2 GT-I9100G.
3. Reboot your phone into ClockworkMod Recovery Mode. You can do that by pressing the Volume Up key, Home button (middle key), and Power button simultaneously until recovery boots.
   • NOTE: Once in ClockworkMod Recovery Mode, use the Volume keys to navigate and the Power button to select an option.
4. Create a NANDroid backup of your current ROM. Go to Backup and Restore and select Backup on the next screen.
5. Go back to main menu and perform a full wipe:
   • Select Wipe data/factory reset and confirm the action on the next screen.
   • Select Mounts and storage, then select Format /system and confirm the action on the next screen.
6. On the main menu, select Install ZIP from SD card.
7. Select Choose ZIP from SD card and locate the RootBOX ROM ZIP file. Confirm the action on the next screen to start installing the ROM into your Samsung Galaxy S2.
8. The AROMA Installer launch. Follow the onscreen instructions. When the installer wizard asks whether to reboot the phone when installation is complete, specify that you don't want to reboot the phone.
9. Go back to the main recovery menu and select Wipe cache partition and confirm the action on the next screen.
10. Select Advanced and then select Wipe Dalvik cache.
11. Go back to the main menu and select Reboot system now to restart your phone.

Great work! You have successfully installed the Vanilla RootBOX ROM based on Android 4.1.1 Jelly Bean on your Samsung Galaxy S2 GT-I9100G.