Samsung also have releases Android 4.1.2 for Galaxy Young Duos. This firmware version is S6312XXAMB2 and only for Galaxy Young Duos model S6312. Before use Odin application to flash the firmware into your Galaxy Young Duos, please make sure that the firmware is compatible to your phone model and the firmware is support your region Network. You can check your phones model version at your phones settings> about device. The firmware S6312XXAMB2 is for S6312 and the step to flash firmware is as below:
Disclaimer: Manually flash firmware into Android phones may void the phones warranty and has the risk that cause your phone brick. Do not unplug the USB connection from PC during the firmware flashing process. Tutorial below is only for your reference and do it on your own risk.
Step 1: Download Android 4.1.2 GT-S6312-SER-S6312XXAMB2-1359973167.zip, then unzip the file. You will get GT-S6312-SER-S6312XXAMB2-1359973167..md5 .
Step 2: On your computer- desktop or laptop, Open Odin 3.04 (Download Odin).
Step 3: Go to settings > Developer Options to enable your phone debugging Mode. Then turn off your phone and then turn your phone in download mode by press (Home+power+vol down) button.
Step 4: Connect phone to the computer and wait until you get a yellow sign in Odin.
Step 5: Add Android 4.1.2 GT-S6312-SER-S6312XXAMB2-1359973167..md5 to PDA.
Step 6: Start flash, sit back and wait a few minutes.
Step 7: Galaxy Young Duos will automatically reboot once installation complete.