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Samsung Galaxy S2 Skyrocket SGH-I727 (AT&T): Upgrading to build UCLE2 of Android 4.0.4 Ice Cream Sandwich

May 23, 2012

Some Android users just can’t wait for official updates to roll out to their phones. The temptation of getting the newest updates before everyone else, even through unofficial means, can drive users to comb forums in search of any leaks. Thanks to the people from BriefMobile and XDA Developers member kennethpenn, firmware build UCLE2 of Android 4.0 Ice Cream Sandwich for the AT&T Galaxy S2 Skyrocket is now available. With a build date of May 8, this leak is based on the Android 4.0.4 Ice Cream Sandwich. Flashers beware–the UCLE2 firmware update appears to have a bootloader update.

If you’re a flashing newbie, have no fear. This update can easily be installed on your AT&T Galaxy S2 Skyrocket through Odin3 in just one click.

We’d just like to remind users that because this is a leak, there may be some bugs in the update. Hopefully, by the time the official update lands on phones, those bugs have been squashed.


  • The instructions in this guide are intended for use with the AT&T Galaxy S2 Skyrocket, model number SGH-I727. Applying these instructions on another device or model may produce undesired outcomes.
  • The information in this guide is provided for instructional and educational purposes only. There is no guarantee that these instructions will work under your specific and unique circumstances.
  • Use these instructions at your own risk. We shall not hold any responsibility or liability for whatever happens to you or your device arising from your use of the info in this guide.
  • Read and understand the whole guide first before actually performing the instructions.


  • AT&T Galaxy S2 Skyrocket SGH-I727
  • Make sure that your battery has a charge of 80% or more to prevent the phone from shutting off in the middle of the flashing process.
  • Backup all personal data on your phone to make sure you have a copy of your personal data (e.g., contacts, SMS, MMS, Internet settings, Wi-Fi passwords, and the like) in case the procedure in this guide erases such data.
  • Download and install the drivers (ATT_I727_GS_II_Skyrocket_USB_Driver_v1_3_2200_0.exe, 23 MB) for your AT&T Galaxy S2 Skyrocket on your computer. (If the link doesn’t work, try this alternative link.)
  • Download the UCLE2 firmware package (I727UCLE2_OneClick-5FCC9DECF4915ED1C0CD7F42799C3783.exe, md5sum: 5fcc9decf4915ed1c0cd7f42799c3783).


  1. On your computer, double-click on the UCLE2 firmware package file to launch Odin3.
  2. Turn off your AT&T Galaxy S2 Skyrocket.
  3. Boot your AT&T Galaxy S2 Skyrocket into Download mode. First, plug your USB cable into your computer. Press and hold down the Volume Up and Power buttons on your phone and plug in the USB cable into your phone. Once the Download Mode screen shows up, let go of the buttons.
  4. The Odin3 window should display an “Added!” message, confirming that your phone has been successfully connected to your computer.
    • If it does not, please check if you’ve installed the appropriate drivers for your phone and try again.
  5. Click on Start in Odin3 to begin flashing the firmware.
  6. If Odin freezes and doesn’t seem to be doing anything, do the following:
    • Disconnect your phone from your computer.
    • Close Odin.
    • Remove your phone’s battery.
    • Re-insert your phone’s battery.
    • Repeat the procedure from step 3.
  7. Once flashing is complete, you’ll see a “PASS” message in Odin3, with a green background.

Congratulations! You now have Android 4.0.4 Ice Cream Sandwich build UCLE2 on your AT&T Galaxy S2 Skyrocket. Enjoy the latest version of this delicious software and let us know how it is in a comment below.