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.

Compatibility

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.

Warning!

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.