Galaxy S was the first installment from Samsung in its much popular Galaxy S Series phone, after Galaxy S we had seen Galaxy S II and S III. Galaxy S III comes with Android ICS and will get Jelly Bean update too, same with Galaxy S II.
But Samsung hasn’t pushed any update for Galaxy S GT I9000 and its currently having latest update of Android 2.3.6. But our folks at XDA has able to release a Custom ROM for Galaxy S, please note that its not a official ROM from Samsung.
If you had Galaxy S GT I9000 and wanna update to Jelly Bean then make sure :-
You had root access,
Your device is updated to Android 2.3.6,
Make a Backup of all your data from Phone, don’t use Samsung KIES to make data baackup. Enable USB Debugging Mode from Setting –> Applications > Development > USB debugging, Make sure your phone is fully charged.
Now connect your phone with computer via USB and put both downloaded files on your SD card and remove USB connection,
Now turn off your phone and enter into Recovery Mode, follow these steps to enter into Recovery Mode :-
Press and Hold your Power Button, Volume Up and Center button at the same time, Once you see Samsung logo release Power button and keep holding Center and Volume Up button and once you see Recovery screen release all buttons.
Now once you are in Recovery Mode select Wipe Data/Factory Reset and Wipe Cache Partition and then reboot your device,
Now Select option Install From SD Card and then select Jelly Bean Package and Google Apps, it will take about 10 minutes to install and once done reboot your phone in normal mode and you are done.