I decided to upgrade Android in my Samsung Galaxy S3 i9300 from version 4.3 to a higher version which is not officially supported by Samsung. See also Wiki on this page.
TODO
- Download Odin flash tool.
- Download an official version of Samsung firmware.
- Unzip the downloaded file on your PC.
- Enter download mode.
- Connect mobile and PC with a USB cable.
- Run Odin and you should see Added!! in Odin log.
- Click on AP button in Odin and choose md5 file you have unzipped.
- Wait until the md5 file is loaded.
- Click on Start button and wait until you see PASS!