AT&T Galaxy S2 Skyrocket Ice Cream Sandwich Firmware Leaked


So, jealous of the fact that the international Galaxy S2 has already got the official Ice Cream Sandwich update but you’re still stuck with Gingerbread on your AT&T Galaxy S2 Skyrocket? Then here’s something that should make you happy. An Ice Cream Sandwich Android 4.0 firmware, UCALC4, has been leaked for the Skyrocket, which you can try on your phone to get a taste of ICS. It seems an official update is surely on its way as AT&T announced a few days ago.

As always, this is a leaked firmware so it can have some bugs and issues as it’s definitely not a final version. But then again, when has that deterred us from giving these leaked firmware a try? Even then, do be careful while trying it out.

Read on to find out how you can update your Galaxy S2 Skyrocket to Ice Cream Sandwich Android 4.0.


This firmware and the guide below are compatible only and only with the AT&T Samsung Galaxy S2 Skyrocket, model number i727. It’s not compatible with any other device and may render an incompatible device unusable. Check your device model in Settings » About phone.


The methods and procedures discussed here are considered risky and you should not attempt anything if you don’t know completely what it is. If any damage occurs to your device, we won’t be held liable.

Pre-Installation Requirements

  1. This procedure will wipe all your apps, data and settings (but it will NOT touch your SD cards, so don’t worry about those). Backup your Apps and important data — bookmarks, contacts, SMS, APNs (internet settings), etc. This Android backup guide would help you.
  2. If you have Samsung’s PC software Kies installed, un-install it first because it may interrupt the flashing process.
  3. Drivers! — it’s important you’ve the proper drivers installed.
    Download Drivers

How to Install UCALC4 Ice Cream Sandwich Firmware on Galaxy S2 Skyrocket

  1. Download the firmware.
    Download Link 1  |  Download Link 2  |  Filename: i727ucalc4-oneclick.exe
  2. Double-click on the i727ucalc4-oneclick.exe file to run Odin, which will be used to flash the firmware on your phone.
  3. Now, boot into download mode on the phone. To do this, turn off your phone. Plug in your USB cable to the computer, but not to the phone. Then, holding the Volume Up and Volume Down buttons on the phone, plug in the USB cable to the phone while holding those buttons. Once the Download mode screen shows up, let go of the buttons.
  4. The Odin screen will say “Added!!” in the message box below when the phone is connected to the computer. If it does not, make sure you have the proper drivers installed on the computer.
  5. Click on Start to start the flashing of UCALC4 on your Galaxy S2 Skyrocket.
  6. Wait for the procedure to finish. After flashing is complete, the phone will reboot, and you’ll get a PASS message (with green background) in Odin. You can now safely disconnect your phone.

    IMPORTANT Note: If ODIN gets stuck at some stage and doesn’t seem to be doing anything, do this — disconnect the phone from the PC, close ODIN, remove battery, re-insert it, and do the procedure again from Step 2. Same if you get FAIL message in Odin.

  7. If you run into any roadblocks while flashing the firmware, let us know and we’ll try to help you out.

Congratulations. You’ve successfully updated to Ice Cream Sandwich Android 4.0 on your AT&T Galaxy S2 Skyrocket with the leaked UCALC4 firmware. Let us know what you think of it, in the comments below.

30 Comment

  1. solomonsright says: Reply

    Sgh – I727R.?????

  2. Rubink33 says: Reply

    Odin process says it flashes but comes up with this and doesnt work whole process takes 2 seconds then bricks the device can recover in normal Odin does any one have just a tar file please help!!!!
    Added!! Odin v.3 engine (ID:10).. File analysis.. SetupConnection.. Initialzation.. Get PIT for mapping.. Firmware update start.. RQT_CLOSE !! RES OK !! Completed.. All threads completed. (succeed 1 / failed 0)

  3. Boothrobertl says: Reply

    Everything went well. Thanks. The only thing I had to do was hit the Volume up arrow to make the application say Added. But that’s it. My friend is VERY thankful that I got it working.

  4. praveen kumar pendyala says: Reply

    ICS update video review. The most stable ICS presently. No broken apps. Gud battery life.
    Thumbs up if you find this helpful. Thank you.

  5. Kioskete says: Reply

    Nice!!! It worked perfectly….
    First time I have done something like this and worked just perfectly!!

    1. Kapil says: Reply

      We’re glad for you 😀 Kudos to Abhijeet!

      1. Kioskete says: Reply

        Thanks to Abhijeet for posting this tutorial!!!
        It is of awesome help!!

  6. Kioskete says: Reply

    Worked awesome looks soo nice, but did not unlock the phone! =( Still asking for the network code! =(
    If someone knows how to unlock the sim (network) let me know….

      1. Kioskete says: Reply

         Wow! Kapil!!
        Jajajaa…… that is supper helpful!! I never thought such a way to get the code! jajaja… It might work!!
        Thanks soo much!

        1. Kapil says: Reply


          Let me know.

  7. Terrancer23 says: Reply

    is this the official update 

    1. Kapil says: Reply

      No it’s not official update. It’s a leaked one, not distributed by Samsung officially.

  8. Isaiah says: Reply

    Did this cause root access to be lost.  I updated to this leak and when I install Su or Busybox I do not have root access.  Is there something that can be changed?

  9. Siddharth says: Reply

    Hey,I live in India and I am using Samsung Galaxy Skyrocket.It is unlocked phone from U.S. Can I install Ice Cream Sandwich on it ?? Please reply at the earliest  

    1. Kapil says: Reply

      Yes you can use the above.

    2. Kapil says: Reply

      So, how did it go? And what’s your view on the update?

  10. me says: Reply

    once i installed ICS the home button stopped working as well as the search button.  i did a factory reset under settings and it seems to have fixed the issue

  11. me says: Reply

    once i installed ICS the home button stopped working as well as the search button.  i did a factory reset under settings and it seems to have fixed the issue

  12. Vinoth says: Reply

    Was able to update perfectly. ICS 4.0.3 on Samsung Skyrocket provides had time on
    1. Exchange email. Not synking properly. Also sink options resets again after configring.
    2. Unable to delete message, results in error message “messaging service stopped”. As a workaround need to select particulat message induvidually using multi select option and delete it.
    3. Some time phone sount dies. Not even alarm sound 🙂 Again statrts working after restart.
    4. Speech, voice command is not detected. Was perfect in gingerbread.

  13. VectorVitale says: Reply

    Are There Certain Places This Will Get Stuck On During The process? Im not sure if its stuck im at SetupConnection…  

    Is this stuck?

  14. VectorVitale says: Reply

    Whoops FAIL had the phone on..

    1. Kapil says: Reply

      If you’re still unable to get it done, I suggest you do this: Install drivers again on PC, Restart PC, Power off the phone, Remove battery for 4-5 seconds and then place it back, do not power on but Boot into download mode, open Odin and then follow the rest of guide to flash ICS on your Skyrocket.

  15. Jimmyjack says: Reply

    Has anyone tried this on the Rogers (i727r) version of this phone? Results?

  16. tim says: Reply

    I flashed this rom over another rom… my home button doesn’t work now… help?

    1. Kapil says: Reply

      Which phone is yours exactly? Remove the battery cover and see the model number under the battery, is it i727?

  17. Adam Gunderson says: Reply

    I was hoping this would remove the AT&T bloatware too.

  18. scuba steve says: Reply

    it keeps freezing up at boot.img i’ve tried 5 times everytime the same spot it stops. reinstalled the drivers, rebooted, and redownloaded odin too. got a i727

    1. Kapil says: Reply

      Have you got this to work? If you need help, let us know.

  19. leechgod27 says: Reply

    I have a galaxy skyrocket i727 from AT&T with last Gingerbread firmware(2.3.6 from at&t).Now i am in india.Recently i did a factory reset and now i have lost data connectivity(though i get full signal and can do calls or messages).
    Even before i used to select frequency bands manually to swap between 2g-3g by dialling *#*#197328640#*#* and i used to get data fine.As there is no such option of selecting ‘gsm only’ or “wcdma preffered” in wireless&networks menu.

    Do i need to have “root” in order to do this process?
    will i get that 2g-3g swapping option after ics upgrade?
    Hows AOKP ICS?

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