Update Samsung Galaxy S2 to Android 4.3 JB Custom ROM CM 10.2

Nexus devices have already started receiving the Android 4.3 Jelly Bean update – the latest Android version. The developers have since started working on the custom test builds for other devices too. This step by step guide will help you in flashing an unofficial CyanogenMod 10.2 test build based on 4.3 JB for Samsung Galaxy S2 model i9100G. Have fun catching up with the latest Android!

Prerequisites to update Samsung Galaxy S2 to Android 4.3 JB CM 10.2 custom firmware:

Backup any important data from your Samsung Galaxy S2 as a complete wipe will be required during the flashing process.
Enable USB debugging option on your device: Settings > Development Options > USB debugging.
Your device must be rooted, unlocked and installed with a recovery tool like TWRP or CWM.
Your device must be charged to at least 60% of power.

Note: the tutorial is only focused on Samsung Galaxy S2 I9100G – the Ti OMAP CPU variant and not the Exynos one. This guide would be helpful for those users who want try the AOSP ROM to see the new features of Android 4.3 JB.

How to update Samsung Galaxy S2 to Android 4.3 JB CM 10.2 custom firmware:

Required files: download the CM 10.2 unofficial ROM zip from here and save it on your PC. Do not extract the contents.

Connect Samsung Galaxy S2 I9100G to your PC and copy the zip files to your phone’s internal memory card. Disconnect your device when copy is done.
Now power off your Galaxy S2 and boot it into recovery mode.
Perform a NANDROID backup of your current OS; important step to revert back to current state. Go to Backup > backup and restore on CWM. On TWRP select Backup, and then choose the system parts you wish to backup.
Wipe data: from CWM recovery mode, select wipe data / factory reset. Confirm the process. You can skip this step if you are on a CM 10.1 ROM.
Time to flash the custom firmware file on your smartphone. Select install zip from sdcard followed by choose zip from sdcard. Locate the unofficial CM 10.2 zip and confirm the flashing process.
Once done, follow the above step for GApps package installation.
When done, return back to main recovery menu and reboot your S2 into normal mode. First boot takes a good 5 minutes so please be patient.

Ta da! You have successfully flashed the unofficial CM 10.2 custom firmware on your Samsung Galaxy S2 I9100G.