Okay here’s the stock I727UCMC1 Android 4.1.2 Jelly Bean for Samsung Galaxy S II Skyrocket AT&T (SGH-I727). This is for those who can’t upgrade on Kies if the main reason is that the device is rooted or running with custom ROM. From this method you can retrieve the official “UCMC1″ firmware update. You will lose root after installation but you can easily rot it again using the latest TWRP recovery and SuperSU.
Disclaimer: We shall not be held responsible if anything happens to your device by following this guide. Proceed at your own risk.This procedure is for advance users only, typical users may only upgrade only thru Kies or via OTA and may not use this method.
– Back up all important files before proceeding, such as contacts,SMS, Emails, photos, videos, apps etc. Although the Internal memory and microSD card are both left alone during after the flash process for this firmware is a non wipe version. But all your settings and configuration will all be reset. So, be sure to have a back up all of it for safety.
– If your device currently runs with any custom ROM, you may ask any assistance first from your ROM developer on how to safely return back to official stock to get rid of any issues.
– Fully recharge your phone’s battery.
– Use Windows-based OSX PC/laptop, Odin will not work on MAC OSX
1) “Extract” or “unzip” the downloaded stock ROM to get the .tar.md5 file.
2) Run Odin3_v3.07.exe on PC desktop
3) In Odin – DO NOT CHECK the RE-PARTITION check box, only both ‘Auto Reboot’ and ‘F-Reset’ left checked.
4) Click on the PDA button then browse to the folder where you extracted the stock ROM “tar file”
5. Reboot the phone in download mode: To reboot the Galaxy S3 into download mode , you need to turn the power off. After it completely shut off, just press and hold the Volume Down key, Home button and the Power ON/OFF button simultaneously.
You’ll then need to press the Volume Up to continue. You’ll be prompted into a warning screen and asking you to press “volume up” if you want to continue or volume down to cancel, just simply press volume up to get into download mode. The download mode then displays an Android robot and say’s “Downloading.. Do not turn off target!!”
5) Once the phone in download mode screen, connect the PC USB cable To Phone. In Odin, the ID:COM box will change its color and its an indication that the device is connected properly to PC. If you still do not get any results, try another USB port on your computer.
6) Click the Start button to begin flashing.
7) Wait until it finishes or watch out for the word “PASS”.
Optional: Once the phone completely reboots, perform wipe/factory reset to get a fresher firmware installation.
1. Hold Power and Volume Up together, this will switch the device into recovery mode.
2. Release Power after holding it for a second but continue to hold the Volume Upbutton until recovery menu appears.
Select wipe cache
Select wipe data/factory reset.
That’s all! your Samsung Galaxy S II I717 now fully installed or restored with the official Android 4.1.2 Jelly Bean (I727UCMC1).
How to Root the “UCMC1″ 4.1.2 version?
To retrieve root access just follow this rooting guide on Samsung Galaxy S2 Skyrocket runs in 4.1.2.