Recently Samsung released Android 4.1.2 XXEMH4 for Galaxy S3 International version (GT-I9300). The update is available through OTA and Kies for the users of India, Sri Lanka, Bangladesh and Nepal. May be this is the final version of Android 4.1.2 for the following countries before the upcoming Android 4.3 update .The update include some battery and performance tweaks.
In this I included the steps to manually flash Android 4.1.2 Jelly bean XXEMH4 to Galaxy S3 I9300 International version using Odin.
1. Backup your important data.
2. Enable USB debugging in your phone.
3. Battery must have 60% or more charge.
4. Disable or Exit Antivirus and Kies if you are installed.
5. Your PC must install Kies or Galaxy S3 driver.
6. This Firmware is only for Galaxy S3 I9300 International Version.
How To Flash Official Android 4.1.2 I9300XXEMH4 in Galaxy S3 I9300 using Odin ?1. Download Official Android Jelly Bean 4.1.2 I9300XXEMH4 for your country from below links.
India | Sri Lanka | Bangladesh | Nepal
2. Extract the downloaded firmware zip.
3. Download Odin v1.85 - Download
4. Now, Extract and Open odin3 v1.85.exe.
5. Power off your phone.
6. Now boot in to download mode. ( Press and hold : Volume down key and Home button ( Center button ) ,now press and hold the power button to boot in to download mode and Press Volume up on Warning)
7. In download mode connect your phone to PC.
8. Now look in to Odin... ID:COM box, it will be yellow with a port name and Added! message will be displayed.
( If not it will the problem of driver or USB ... check both )
9. In Odin..Click PDA and browse the extracted firmware folder and select I9300XXEMH4_I9300ODDEMI2_I9300DDEMG2_HOME.tar.md5 finally Click Start button.
10. After complete update Odin will show PASS on top left and phone will reboot. now unplug phone from USB.
That's it .... Done .
If the phone stuck at the boot screen...
1. Remove and reinsert your battery.
2. Now boot into recovery mode. (Volume up + Home + Power )
3. Apply wipe data/factory reset.
4. Apply wipe cache partition.
5. Finally reboot system...
Go to the below post to root the firmware