Finally, Samsung release jelly bean official update for Galaxy ACE 2 I8160. But only for China, Portugal and Greece.

#UPDATE:27.7.13 Now, it already supports most of the regions. But the only difference is just customization in app (As long as I discovered). I used Jelly Bean package for Portugal region even I am not from there. I hope Samsung will release update for more region.

Please bear in mind that, by accessing the internal system and OS, you will lose the warranty. So, take your own risk.

1. Backup all your necessary data (Recommend Samsung Kies to backup all your data)
2. Download Odin and official firmware d XXMC8 Jellybean 4.1.2 firmware Package for Portugal (TMN) region.                                                                                              → For other regions, explore more on http://samsung-updates.com/device/?id=GT-I8160. To start installation, Go to Download mode in device by pressing Volume down key + center key simultaneously                                                                         You may need to remove current ROM. Restart device by pressing Volume up + center key, then choose “wipe data/factory reset“. It remove all of your data. So, be sure you backup.
3. Open Odin in your computer and connect your device with computer
4. After a minute, the ID : COM section in odin will turn yellow indicating that all the drivers have been installed successfully. Click on “PDA” to select the .tar file which you got upon extraction of firmware zip file of XXMC8. Once the file is selected, click on “Start” to start the process of firmware update.
5. After the firmware is updated successfully, the phone will be rooted. The rebooting time will take longer since the device install all the apps and rebooted again and again. Once you will see the home screen, disconnect the device from computer.
6. To check the firmware update version details in your device, head over to the path “Settings > About Phone > Firmware Version” where the firmware version details will be mentioned.

For more detail – http://androidadvices.com/manual-update-galaxy-ace-2-i8160-official-jellybean-412-xxmc8-firmware/2/