Your long wait is over, official Jelly Bean stock firmware is now available for your Galaxy S3 GT-i9300. (Please DO NOT FLASH on U.S./Canadian GS3s!!!)

This first official Jelly Bean stock firmware is for Poland GT-i9300 but it is compatible with any GT-i9300 models and does come with all the languages (as shown in installation video below).

We’ve seen much of the official Jelly Bean features with the leaked JB ROMs but pretty much you get all of the Jelly Bean butter-smooth UI, Google Now/Google Cards, and some more enhancements Sammy added in various different parts.

It looks pretty solid and definitely you should upgrade. If you are on stock rooted ROM, you can probably install this ROM without doing a data wipe/factory reset. However, if you are coming from a custom ROM, my advice is to do a data wipe/factory reset in CWM Recovery before installing.

Try it out and let me know how the official JB goes for you!

You can also use this method to unroot your phone!

Download:

Download Official Jelly Bean Stock Firmware for GT-i9300 Poland Edition

Mirror

Credits – MAX

For those of you who want to unroot your Galaxy S2 i9100 to the latest ICS “official” stock
ROM, you can do this easily using ODIN. (or Heimdall for Mac/Linux).

Step 1. Put your Galaxy S2 i9100 into download mode by holding down Volume Down, Center button, and Power button together for about 10 seconds until your phone reboots and you see the warning sign.  Press Volume Up button to enter download mode.

Step 2. Connect a micro-USB cable to your Galaxy S2 from your computer.

Step 3. Download stock ICS ROM and unzip.

Download stock ICS ROM

Step 4. Download ODIN, unzip, and run the program.

Download ODIN

Step 5. When ODIN runs, you should see a yellow highlight with a COM appearing.  If you don’t see it, download Samsung Kies and install.  Then plug-out and plug in your micro-USB cable to your phone, you should see it now.

Step 6. Choose “PDA” in ODIN and choose the stock ROM file you downloaded/unzipped earlier.

Step 7. Hit “Start” and your phone should start unrooting/unbricking back to ICS official stock ROM.

Step 8. Your Galaxy S2 i9100 will reboot after 5-10 minutes.

Step 9. Your phone should now be on stock ICS.

Credits – MAX