Galaxy S II

How To Update Samsung Galaxy S2 i777 with Gingerbread 2.3.5 Firmware

Galaxy S2 I777 LogoSamsung Galaxy S2 users on att network now have a reason to smile as an all new update has arrived in the form of Gingerbread 2.3.5 and is dubbed as UCKJ1. Please note that this is not the official release of the firmware which is launched by either the att or the Samsung Electronics and is the leaked version of the firmware. In this page we will see about the list of enhancements and new features which this version of firmware brings along and also we will see the list of pre requisites which in one has to follow before you proceed to update the phone.

Rooting Information:
Applying this firmware update in no manner will be rooting the device, so there is no fear of losing the warranty. Also, just in case if you have already rooted the device then after applying this update the rooting access will be revoked. To root the phone again, we will be coming up with a new article wherein we will check out on how you can root the same. But please note that rooting voids the warranty.

Please note that we should not be held liable or responsible in any manner if anything wrong happens to your device which is the most unlikely if you follow the instructions as prescribed in the due course of this article. It’s very important to follow the instructions or else the phone may even get bricked.

For all those who are already on the custom ROM firmwares then you will have to ensure that you clear all the cache data from the recovery mode. The recovery mode can be entered by pressing  Volume UP on Volume Down Key + OK button, and holding both simultaneously press the Power Button. In the recovery mode choose the options like Wipe data/factory reset and also you need to select Wipe Cache partition after which you need to reboot your device by selecting reboot system now.

Just in case if you are using the Voodoo Kernels or any of the Voodoo products in your Samsung Galaxy S2 then it’s very necessary to disable the same or else it will create issues in updating the device. You can disable the Voodoo Lag fix from the “Advanced” option which will be there in the recovery mode. Also, you will have to clear the battery stats in your phone from the recovery mode itself.


There are few enhancements as well as the new additions which are listed below:


  • Battery charge has been substantially increased up to 15%,
  • Android Market Place now works perfectly even on slow data speeds,
  • Supports latest version of Android Market Place 3.2.0,
  • Higher quadrant ranks when measured with Antutu Benchmarking tool,
  • Home button lag as well as the Lock screen Bug has now been fixed,
  • Internet browser has been modified for faster surfing speed,
  • Wi Fi bug of frequent disconnection has been fixed,
  • Free space have been improved marginally,
  • GPS Connectivity in indoors is not an issue anymore,
  • Now supports Rooting ,
  • Bluetooth Pairing error which some users reported last time too has now been fixed in this firmware

New Features:

  • Over scroll Glow is now part of the standard features,
  • Download Managements folder algorithm has been modified to support all email attachment downloads.

Note: You need to follow a detailed list of Pre Requisite instructions which we have compiled just for you so that no issues are faced if you follow them before proceeding to update your phone.

Complete List of Pre Requisite Instructions

Once you are done with the following of Pre Requisites, let’s proceed with the procedure to update Samsung Galaxy S2 I777 with the latest version of Gingerbread 2.3.5 UCKJ1 in the next page.

Procedure to update Galaxy S2 SGH I777 with Gingerbread 2.3.5:

  • First up you will have to download the Odin executable file from here. Please note that just in case in the process of extraction the password is asked then you need to enter the password as “”. So, once the password is entered you will see that Odin will be opened up as shown in the below screen capture.
  • Please note that only the Odin which is mentioned in the article should be used, if you continue to proceed using the Odin which you downloaded from any other source apart from the “” then we should not be held responsible for the damage done to your device as that may or may not update your phone.

Odin for I777

  • So, once the Odin is opened in your computer you will now need to turn off your phone so that you can then enter into the download mode which is in other words is the safe mode. The download mode can be entered by pressing down on Volume Down Key + OK button, and holding both simultaneously press the Power Button. Note that if the device boots up in the normal mode then you will need to again try the procedure to enter into the download mode as without download mode its very dangerous to proceed to the next step.

  • Once you enter into the download mode, with the help of the USB cable which you got at the time of purchase connect the phone with the computer while keeping the Odin opened in your computer. Once the phone is connected you can see the indication that the phone is connected and also the ID : COM section will turn Yellow, after this all you need to do is to just click on the “Start” to start the proceedings of the firmware update. In the process of firmware update ensure that you are not interrupting the process of firmware update or else you may face issues like phone not turning ON.
  • As soon as the firmware update is successfully installed, the phone will be restarted automatically and then you will have to select the Language Preferences followed by the Google Account credentials. After this you will see that the home screen is being shown which means that the firmware has been successfully installed. To check that the firmware has been successfully update dor not, you need to go to the path “Applications > Settings > About Phone” where you will see that the firmware version will be UCKJ1 2.3.5 Gingerbread version.
  • That’s it you now need to turn Off the phone as you will now have to enter into the recovery mode to clear off all the cache data which is there in your phone. The recovery mode can be entered by pressing up on Volume Down Key + OK button, and holding both simultaneously press the Power Button. In recovery mode you will have to select options options like Wipe data/factory reset and also you need to select Wipe Cache partition after which you need to reboot your device by selecting reboot system now.

That’s it, so in this way you have successfully updated the phone. Do let us know in the comments section below if you face any issues as we will try our level best to address all your issues at the earliest.



  1. sarah

    August 12, 2012 at 2:51 pm

    galaxys s2 displays ” firmware upgrade encountered an issue. Please select recovery mode in Kies & try again” how can i fix this ?

  2. Barry

    June 28, 2012 at 9:19 pm

    This also worked great when I wanted to get rid of ICS and go back to Gingerbread.

  3. sonu

    April 22, 2012 at 1:54 pm

    Worked great on my i777…
    thanx bro……..

  4. Michael

    March 18, 2012 at 2:54 pm

    Url is not working 🙁

    • Neela Pradeep

      March 18, 2012 at 3:00 pm

      we have changed the links, kindly check now!

  5. sudhir nani swarna

    February 25, 2012 at 10:24 am

    Great it works please use volume button to scroll to items and home button to select

  6. tazeem

    February 5, 2012 at 12:01 pm

    i have an samsung galaxy s2 till i have to the update when i tun on my bluetootch the mobile freezing and keep restart so many time and then the bluetootch turn off by itself :S any solution

    • Neela Pradeep

      April 6, 2012 at 12:44 am

      try updating with the latest firmwaere from

  7. Arun

    January 12, 2012 at 9:52 am

    Hi Neal,

    Will AT&T Samsung Galaxy S2 get locked after applying this update. I see contradition in 2 of your replies for the same question. In one(asked by Mallik on Dec 9) you said it will not lock the phone and in other(just above my post) you said don’t update, it will lock your phone. Can you please tell whether to apply update on AT&T US version of Galaxy S2 or not. I dont want my phone to be locked.


  8. GeeVi

    December 22, 2011 at 5:55 pm

    hi admin….
    I got a doubt……can u clarify it?

    1-My friend bought an AT&T version of SGS2 in USA.
    2-He came to India this month and presented that mobile to me.
    3-Now an update is available to SGS2.Do I need to update??
    Actually i am happy with the present version 2.3.4.
    4-If I update will there be any problem?

    • NeaL Pradeep

      December 22, 2011 at 7:05 pm

      dont update or else your device will be locked!

  9. Mallik

    December 21, 2011 at 7:50 pm

    Hi Neal,

    When I got my AT&T Galaxy S2 (Model SGH-I777) unlocked here in india, then from that moment I am unable to hear any audio when I make or receive the call, Where as my phone rings perfectly when I get a call, but the moment I pick the call then I dont hear any sound. Also tried with a bluetooth headset and earphones, but still the same problem. Also when I make a call to another cell, that phone rings , but I dont hear any dial tone in my phone. However I am able to send/receive SMS without any problem. Also after unlocking my phone the back soft key and the search soft key are not working. Please kindly suggest.

    – Mallik.

  10. Tahir

    December 19, 2011 at 6:09 pm

    Hi Neal,
    I desperately need ur help…
    I have done whatever you told me but now I am getting the Services & logo of AT&T…
    even nothing is happening after pressing all the 3 buttons together (Volume+OK+Power), the fone get started as NORMAL
    pls suggest…help!!!

    • NeaL Pradeep

      December 20, 2011 at 7:09 pm


  11. Tahir

    December 19, 2011 at 11:00 am

    Hi Neal,
    I live in India, can I update with this firmware?

    • NeaL Pradeep

      December 19, 2011 at 11:21 am

      yes tahir you an apply with this firmware!

      • Tahir

        December 19, 2011 at 11:26 am

        does it void my warranty?

        • NeaL Pradeep

          December 19, 2011 at 3:01 pm

          no tahir, it wont void the warranty!

      • Tahir

        December 19, 2011 at 11:29 am

        is ICS (Ice cream sandwich) or 2.3.6 is available for India?
        if Yes then how can I update it?

      • Tahir

        December 19, 2011 at 1:57 pm

        I have tried to do it, but it got failed & on the screen I am getting a msg ” Select Recovery Mode in Kies”
        but when I am trying Recovery in Kies then I am unable to do it
        pls HELPPPPP !!!!

        • NeaL Pradeep

          December 19, 2011 at 3:09 pm

          why you tried recovery via kies, we never mentioned in the article to do so. Please stick to the procedure!

  12. Richard

    December 15, 2011 at 5:44 am

    So I install this update on my S2 and my dad’s and both of us are having the gallery forced close issue. Is there a fix for this yet?

    The update have been almost perfect for me. Only that little problem.

    • NeaL Pradeep

      December 20, 2011 at 7:35 pm


  13. Mallik

    December 9, 2011 at 1:33 am

    Hi Neal,

    Just a quick question! I have an AT&T Samsung Galaxy S2 (Model SHG-I777) and I got it unlocked. Now if I upgrade the firmware to Gingerbread 2.3.5 from 2.3.4 which is currently on my phone, then will the phone get locked again? Please clarfy.


    • NeaL Pradeep

      December 9, 2011 at 6:20 pm

      no, the phone will not get locked!

    • Tahir

      December 19, 2011 at 10:46 pm

      Hi Malik,
      I need your help as ACCIDENTALLY, I have applied the AT&T firmware in my Galaxy S2 (Indian version) & now whenever I am pressing Volume Down+OK+Power button simultaneously then nothing is happening, means its not going to Download Mode…
      Pls help & tell me the Process/Procedure to go to Download mode to start NeaL process mention above.
      Pls Help!!!!!

      • NeaL Pradeep

        December 20, 2011 at 12:23 am

        the download mode procedure remains the same!

  14. SP

    December 8, 2011 at 12:28 am

    I have been trying to install the firmware and it has been stuck at the following step for about 25-30 minutes:

    NAND Write Start!!

    Do you know why it is taking this long or is it suppose to take this long?? PLEASE HELP!

  15. Z

    November 25, 2011 at 1:56 am

    my phone is stuck in recovery mode! i cannot select anything!

    • NeaL Pradeep

      November 25, 2011 at 10:59 am

      remove the battery and re apply the update! which is the phone you are applying this?

  16. javier

    November 6, 2011 at 6:54 am

    is it safe to have your phone rooted and then update or will something happen

    • NeaL Pradeep

      November 6, 2011 at 2:13 pm

      this update doesnt require you to root the device!

  17. allen

    October 29, 2011 at 12:13 pm

    Actually there’s another problem that I found is that the photo gallery crashes everytime I go to click on the picture to view it in full screen. Anyone experience the same issue?

    • NeaL Pradeep

      October 29, 2011 at 6:18 pm

      go to manage apps and clear the data and clear the cache of the gallery app!

    • Kevin

      November 1, 2011 at 12:06 am

      I have the same problem with the gallery crashing when trying to view picture in full screen. I cleared the cache as suggested but it doesn’t fix the problem.

      Also, to get into download mode on the i777, you need to hold down the volume up and volume down buttons at the same time while you plug the phone into your computer.

      • chuck G

        November 23, 2011 at 6:10 am

        I’m Having the same problem with the gallery? Any suggestions?

  18. Allen

    October 26, 2011 at 9:12 pm

    Is anyone experiencing issues with the bluetooth? It seems to be dropping in and out for some reason. I think it maybe because of the firmware because with 2.3.4 I didn’t have this issue.

  19. Goran

    October 25, 2011 at 3:06 am

    If i update this on my galaxy s2 i777, will i lose all my contacts/apps and stuff???

    • NeaL Pradeep

      October 25, 2011 at 1:50 pm

      yes you need to create the backup of the same!

  20. ruksan

    October 24, 2011 at 11:04 pm

    You told to start the phone in download or safe mode, but it seems they are two different mode in my SGH-i777. Download mode starts when I press volume up+down +power keys and shows big yellow triangle. Where as safe-mode comes when tapping setting key when phone is booting.

    In download mode, I can’t see the content of phone whereas in safe-mode it is like safe mode in computer. I’ll have access to all contents of my phone but there will be “safe mode” printed at the left bottom of the screen.

    Now I’m pretty confused, it is download mode (with big yellow triangle) or safe mode (like normal screen) we need to use?


  21. cuco171987

    October 23, 2011 at 10:08 pm

    I want to update my Galaxy S2. Before update I get into recovery mode and i choose Wipe data/factory reset and also Wipe Cache partition. After that I reboot. I get my phone into download mode, plugged USB cable and opened OdinExcution. I pressed START and it FAILED( All threads completed. (succeed 0 / failed 1) .
    Now on my phone is – Firmware upgrade encountered an issue. Please select recovery mode in Kies & try again.
    Before updating on my phone I had 2.3.4 I9100XXKH3 – Litening_Rom_v6-1.
    Where is the problem? can you help me what shell i do?

  22. hamid

    October 20, 2011 at 5:38 pm

    hi how update s2 with unroot. is it possible 2 update s2 without root.

    • NeaL Pradeep

      October 20, 2011 at 7:52 pm

      you can unroot by applying the update once again!

  23. Ibthesam

    October 19, 2011 at 7:50 pm

    WOW !! This site is amazing & the topic was very helpful……..

  24. Mark

    October 19, 2011 at 7:09 am

    Hi everyone. I had the same problem getting stuck with the factoryfs.img My work around was running the odin file as administrator first. After that it worked like a charm.

    semi-spam so people won’t skip over this

    My work around was running the odin file as administrator first.
    My work around was running the odin file as administrator first.
    My work around was running the odin file as administrator first.
    My work around was running the odin file as administrator first.
    My work around was running the odin file as administrator first.

  25. Eisa

    October 19, 2011 at 5:03 am

    I followed the steps for upgrading my samsung galaxy s2….but then, in the end message appeared to my phone screen as follows… Firmware upgrade encountered an issue. Please select recovery mode in kies & try again. Again, I followed the rights steps for recovery mode but, same message appeared to my phone screen. I turned my Phone off for few minutes, the try downloading again, but nothing changed. What will I have to do now?

  26. mike

    October 17, 2011 at 9:52 am

    Worked great on my i777, but I noticed that the feature of holding the home key to access shortcut menu no longer works? Maybe that was part of the fix to the whole home key speed issue?

  27. nem

    October 16, 2011 at 11:45 pm

    Can i load this on a normal i9100 galaxy s2?

  28. John

    October 16, 2011 at 8:44 pm

    After downloading to phone for about 90% and after I get All threads completed. (succeed 0 / failed 1)

    • John

      October 16, 2011 at 8:48 pm



      • NeaL Pradeep

        October 16, 2011 at 11:16 pm

        check with another pc!

        • Ruben

          December 10, 2011 at 12:16 am

          nah, that didn’t work in my case … Pls, help me with a workaround.

  29. Ian

    October 16, 2011 at 8:15 pm

    I dont know what happened. could ayone help me out? i booted into safe ,but now nothing is happening. my galaxy s2 is just on “Odin Mode. Downloading…Do not turn off target”


  30. Joe

    October 16, 2011 at 1:58 am

    Did it exactally as it says.When I open Odin it turns yellow when I plug in my phone it goes through this and nothing happens.Just freezes
    Odin v.3 engine (ID:6)..
    File analysis..

  31. Atik

    October 15, 2011 at 7:40 pm

    Hi Neal,
    I live in Kuwait, can I update with this firmware?

    • Atik

      October 16, 2011 at 7:04 pm

      Hi Neal, still waiting your reply……………………..

    • NeaL Pradeep

      October 17, 2011 at 9:32 am

      yes you can update with this firmware!

  32. mackm

    October 15, 2011 at 4:00 pm

    How long does the update take? I wait for over an hour nothing happens and i have to interrupt process.

  33. mohd

    October 15, 2011 at 4:13 am

    can I install this ? I already have the Gingerbread 2.3.5 XWKI8 on my S2 ? Thanks

  34. FIE

    October 15, 2011 at 2:19 am


    • NeaL Pradeep

      October 24, 2011 at 9:03 am

      apply the update which is available for I9100, things will be sorted out!

  35. Emile

    October 15, 2011 at 1:46 am

    can this update be applied to a normal galaxy s2 i9100??

    • NeaL Pradeep

      October 23, 2011 at 9:29 pm

      no, its not for the normal galaxy s2!

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