After searching a hell lot on internet for jellybean of Galaxy S Duos,I finally found one :) :D
Samsung Galaxy S Duos comes with Android 4.0 Ice Cream Sandwich and no known official update yet has been released for the device. Android 4.2.1 update for Galaxy S Duos can only be obtained using CyanogenMod 10.1 custom ROM to maximise its capabilities.
CyanogenMod 10.1 custom ROM includes Android 4.2 Jelly Bean features such as Google Now and Project Butter, personalisation options and less bloat ware compared to the stock ROM.
Alright...Here are the steps...
Alright...Here are the steps...
1. Connect your Galaxy S Duos to your computer then copy the CyanogenMod custom ROM (click here to download. Do not extract any of them.
2. Disconnect your phone from the computer and reboot it into Recovery mode. You can use the ClockworkMod recovery app or turn off the device then press & hold Volume down + Home + Power keys to reboot into Recovery mode.
3. Inside the Recovery mode, create a nAndroid backup of your current ROM. Select "backup and restore > backup." You can restore the ROM anytime you desire.
4. Now perform a full wipe on your device. Select "wipe data/factory reset" and "wipe cache partition." After that, select "advanced > wipe Dalvik cache."
5. Go back to the main menu and select "install zip from SD card > choose zip from SD card" then choose the CM10.1 you have copied earlier on the external memory.
6. Once the installation is complete, go back to the main menu and select "reboot system now."
7. The device will reboot itself and may take up to 5 minutes to reach the home screen.
Congratulations! Your Samsung Galaxy S Duos is now running Android 4.2.1 Jelly Bean with CyanogenMod 10.1 custom ROM.