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

by: Carl ParkerMay 23, 2012
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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.

  • Ray07

    When is the At&t GS2 going to see an update? Wow, I’m very dissatisfied with Android.
    I am hoping Apple does not release a revolutionary device. I just might have to jump ship.
    Sorry Google, but you need to get a better grasp over your devices once they reach carrier level. Carriers do not care about timely updates. They are going to receive their monthly payment regardless. Google, you need to man-up and learn a few lessons from Apple.

    • Great idea. Blame Google for a carriers issue. It’s not like there is a nexus line that get all updates straight from Google or anything.

      Oh wait. There is.

      • Ray07

        Yeah, at a hefty price which 70% of Americans cannot afford. I’m not willing to pay $450 for a phone that will be worth half of that in less than 8 months.

        • If people cant afford to save $450 should they really be looking at high end smartphones and plans in the first place?

      • Person

        Yeah, it’s the carrier’s fault. But carriers don’t give a flying fuck if the updates are on time. Imo all updates should work like the nexus line, the way updates work now is the only thing apple has going for them.

  • Patriot7100

    Installed and seems to run awesome. Extremely fast. One bug I have noticed. While in the phone screen, when switching to the contacts, the phone screen seems to resize.

  • Itsbuck

    Installed…. the modem/radio needs work for weak signal strength. Losing data connectivity frequently as well

  • Moe

    Ran into some issues at first, but turns out the firmware file hadn’t downloaded completely the first time around….make sure that it does! All that mess aside, ICS is beautiful on the skyrocket, love it. Thank you devs!

  • Conan

    AWESOME ! ! ! It worked for me ! ! ! :D Thanks a bunch ! !

  • Aar4000

    Just installed on my skyrocket, and its even faster than before now. I haven’t ran into any bugs, this build seems very stable..

  • Johan

    What about the battery life?

  • Nagylm

    Awesome!!!….Works flawlessly!!!

  • Tkolodziejczak83

    I’ve yet to test it out, but being a phone noob, your instructions weren’t clear enough for me to get it into download mode. Googling helped and led me to this:
    Explained it a lot better for me, and now it’s working.

  • Ted Hofbauer

    Odin stops in Setup connection step. Any recommendations

  • Ted Hofbauer

    do I need to root my phone first

  • Karas1979

    I like it. A few small bugs with contacts sync and the black border under the text message box when using Swype doesn’t disappear anymore but other then that all good

  • Donald

    Installed without a problem. Programs appeared to run faster, but the leak lacked the UI polish I would expect at this late of date. The ROM’s font was inconsistent throughout the experience and in applications. I also don’t think it was downloading all of my FB friend’s photos into my contact book and my Yahoo calendar never came down.

  • Sutheesh

    How to Root it to be use outside US. I am facing problem with wifi hostspot and tithering.
    Can you help me remove all ATT apps??

  • Nalta45

    When I plug in the charger I get a “Battery Disconnected” message and it doesn’t charge. When the phone is off I get the yellow battery error symbol. I swapped out the battery, still the problem remains. This only happens on ICS

    • Nestor Robayo

      Same thing happen to me in gingerbread just turn off your phone, take the battery our and let it sit for a few mins then put back in, and start charging. If you don’t see admiration mark problem solved. Then turn on. You can turn on then charge. If you like to get better results.

  • Nuvira

    I got FAILED (red) screen rather than PASS(green). any idea ? a log below:
    Enter CS for MD5..
    Check MD5.. Do not unplug the cable..
    Please wait..
    Checking MD5 finished Sucessfully..
    Leave CS..
    Odin v.3 engine (ID:4)..
    File analysis..

    All threads completed. (succeed 0 / failed 1)

  • Nestor Robayo

    It worked for me. I did the backup con titanium but I lose all third party apps I have to download again. ui does loook like ice cream sandwich launcher how do i get ice cream sandwich launcher

  • Netonet40

    I flashed this ron it worked in the beginning but when I root it and try to restore some of my apps. And data something went wrong because the screen keep on showing like the process that were going on up and down the screen blocking the visual

  • Sagisam

    Thanks. I flashed it without any issues , it shows up as 4.0.4 in the settings.
    But the look and feel is same as 2.3.6. (installed Go Launcher EX to feel it as 4.0.4)
    Also camera software is not upgraded. it is still GB version.
    Any info/updates on how to upgrade the camera sw as ICS…

  • pete – frisco tx

    flashed my skyrocket today…having trouble the wifi keeps turning off setting keeps crashing…suggestions

  • LiquidKnight

    AT&T Samsung Galaxy S2 Skyrocket I727 ICS 4.0.4 review::..

    (I did not back up before I did this. Wanted a fresh start. Using WIFI at the moment.)

    Just finished the download and install of this ICS 4.0.4. My results with a brief over-view of the ICS 4.0.4 that is now on my phone are the following:

    ))Minor millisecond lags from finger input to screen movement output.

    ))Very Sharp looking interface despite very fiew (to the eye) changes by the cover.

    ))Much nicer lock screen with the ability to swipe to any new SMS messages.

    ))Very nice swipe to kill apps in the top display bar.

    ))Nice task switching VIA (holding the home button.) In fact, very nice!

    ))I got new contacts! (they were never in my contacts before and I don’t know who these people are. Funny though..)

    ))Speed seems to be the exact same as a fresh Android 2.3.3 whatever.. (AT&T’s stock SGS2 Skyrocket ROM.) Not much difference with speed. (No benchmarks yet. keep this in mind)

    ))Not as fluent as before ICS 4.0.4.

    ))Very Very Very Very happy to see google Chrome browser on here. Very fast, Very fluent. Much better than gingerbread stock for this device. Much quicker web page load times. (based off of WIFI at 6MB up 2MB down. thats what you get when you don’t pay cox for 2 months strait.)

    Over all this seems to be a very stable ROM. I would suggest over all, that you will enjoy this. In fact, I give you my word. But keep in mind that I have only been playing with this new setup very briefly and quickly so good luck. I will comment back on here if I notice any severe problems. I am usually good for my word, So I will be back if I notice anything alarming. M!key out! — CHEERS!

    • David

      Oh good, the stranger on the internet has given me his word. I feel better about it, now. ;)

  • LiquidKnight

    A followup to my post earlier. Well I said I’d post again if there were any problems. In fact there aren’t any others I can find after a deep search for them doing everything imaginable to the phone. It is running really fast. I don’t know what the other users are having a problem with as far as the radio goes; but mine in fact has 2 more bars of radio strength than before. So it looks to be the radio has improved. I am in the same area, the same room of my house, and yes, this is 4G we are talking here. Not LTE, not even 4G hspa+, just pure 4G. I am on the east coast located in Virginia. Perhaps having the mountains around gives a greater coverage area considering the towers are on top of mountains.

    There are so many variations as to why there are differences from user to user. I consider myself to be a very technological with almost anything.


    A quick rundown..

    I have a custom PC – Cooler Master full tower, Asus mobo with support for sandy-bridge 775. i7 4.5ghz OC, two amd xfx 6980 gpu cards w/ 1300 watt gold cooler master psu, antec hydro-cooler (sealed water cooler (much better than regular radiators) I run at no higher than 32 celsius), 16 gigs sniper ddr3 1866 ram, 3 ters of space; need I keep going?

    Not to sound cocky from what I’ve spoken from, but, I do know what I’m talking about; had a droid. Rom Manager, Rom Toolbox, Jrummy.. Had HTC Thunderbolt; I know what’s up. I again say that I feel this ICS that is offered here on this page is pretty safe and feels a lot more smooth than I had given credit for earlier.

    There are so many changes to the phone that aren’t even mentioned in the description and they are nice ones too! Too many to say, and it’s worth finding out for yourself; so give this 4.0.4 a try and big thanks to
    Carl Parker.

    • need you keep going? you better stop before your head explodes.

      • yeah, a bit much; but I don’t guess anything on here matters anymore because android 4.1 Jelly Bean is coming out right now and it won’t be long be4 Skyrockets have it too.

        • David

          Yeah, right.
          If AT&T hasn’t rolled out ICS for Skyrockets yet, I’m sure not holding my breath for Jelly Bean. If I were you, I wouldn’t exactly plan on getting it for Skyrocket, either.

    • is NFC enabled after the update?

  • Todd Wells

    Anybody know if NFC is enabled with this ROM, considering that the Galaxy S III on AT&T will have it enabled I was hoping it would show up here also?

  • Neeraj

    why does the “look and feel” look and feel the same ???

  • Neeraj

    still looks like crap on my skyrocket no UI change.. :(

  • alwaysbeendroid

    How do i root my phone after installing this leak. I like thus far but want to change add on cyanogen mod. thanks in advance

  • alwaysbeendroid

    How do I root my skyrocket after installing this new ICS leak. I cant find the USB debugging option in the settings and I really want apply cyanogen mod.

  • Dale

    How do I undo this. Not happy with it and would rather wait for the official update.


    Can I unroot this baseband UCLE2?

  • POandroiduser

    I am really upset after updating to ice cream from receiving a message from ATT that a new update was available….normally with any android i have own, unless I rooted it, I updated it. I am not so happy this time. Just two days ago I had discovered that my phone had the ability to screen capture, if my phone hadn’t frozen for a second, I probably wouldn’t have hit a couple multiple buttons that we normally hit like home and power to get out of frozen mode and found out this nifty little feature that I thought only iphone was capable of. So he I go and update my phone and I wanted to screen shot the new interface to another fellow skyrocket and low and behold….nothing but task manager popped up! I mean wtf. How can samsung go from having a cool feature to getting rid of it for the following update. I wish that I could undo this update. If anyone knows how without bricking my phone I would love to know.

  • Vignesh

    I have just installed the ICS on my phone. It didnt feels good. I doubt if the video driver is not the correct one. It seems to lack the sharpness or its looking blur. The fonts seems to be uneven.
    Most of all, the phone is struggling to play HD videos. Anyone experienced this lag on your phone upon playing HD content ?

  • jcastro

    After I got the update, I don’t know how to screen capture anything…someone please help!

  • thad

    Thanks! This worked well when i tried to update my Samsung SII to ICS using Kies and it froze on the boot screen.

  • William



    I have 2 skyrockets, one from the release last november and another from about 2-3 months ago, so a newer build.
    I upgraded both phones to ICS, The first releaseed skyrocket reboots and crashes non stop after the upgrade. I cant even hardley use it as a smart phone anymore with out terrible issues and constant crashing, the other skyrocket (a white one) which was again, purchased only a couple months ago has taken the upgrade flawlessly. Both phones have the same apps, except the one with no problems has more junk/ crap apps on it, games and what not. I only use the other for work so the apps on it are nothing major. Which makes no sense at all. this is either 1- AT&T’s way of making older phone users be forced to buy a whole new phone, and pay the $600-$700 because there for sure wont be an upgrade option available. Which would not suprise me with they’re efforts to force people off unlimited DATA plans, Or a problem with the compatibility of first builds of the skyrocket and ICS not working together. It would not suprise me at all with all the crap I went through with AT&T and having the unlimited plan on my phone if this is they’re way to force unlimited data users to have to purchase another phone to make up for potentially lost dollars. My newer skyrocket runs on a limited data plan, no issues from upgrade, and my unlimited data plan skyrocket, FUCKED, something is fishy to me.
    Heres the kicker, are you skyrocket users with all the problems on a grandfathered unlimited data plan?
    its too weird that I just so happen to own 2 of these and only the one on unlimited data is having the crazy crashing issues.

    What ever it is, makes little sense,
    Both phones are rooted with the exact same software and have had 0 (zero) issues until this upgrade where only ONE of the phones is recieving terrible problems from the upgrade,

    I also completely factory rebooted the phone with the problems today.
    The results is having to reset up the whole phone all over again, with the exact same issues as before, nothing better was noticed after wiping the whole phone and reprogramming to start completely over as if it was a new phone, except it rebooted with the ICS software that started causing all these terrible problems,

  • dud i did the update i have the new androit but i can’t take screen shot now help someone…?????? i’ll like to know how???

  • Neworld Ratsman

    Need help with AT&T Samsung Galaxy S II Skyrocket SGH-I727 what i did was rooted is when it restart it keep vibrating & restarting sometime it shows logo try to do a factory reset wont stay connected to port longer then 9 s’ batt life is haft full