93 thoughts on “[TUTORIAL]: How to install/flash official ICS 4.0.4 on Sony Xperia U ST25i/a

  1. Hello Mod
    am having problems flashing my xperia u to ics 6.1.1.b.1.100 first off it almost tries to flash and then it got to the point after
    -start flashing
    -processing loader
    -checking header
    -ending flashing session
    -error flashing. Aborted
    please what can i do to solve this, please help.

  2. it ignored my simlock.ta ! i checked wether my mobile is sim locked but there is no [x] on simlock also
    and bootloader is still no ,,, please help

  3. Following this guide, it gives me:
    27/053/2014 23:53:14 – INFO – Start Flashing
    27/053/2014 23:53:14 – INFO – Processing loader.sin
    27/053/2014 23:53:14 – INFO – Checking header
    27/053/2014 23:53:14 – ERROR – Processing of loader.sin finished with errors.
    27/053/2014 23:53:14 – INFO – Ending flash session
    27/053/2014 23:53:14 – ERROR –
    27/053/2014 23:53:14 – ERROR – Error flashing. Aborted
    27/053/2014 23:53:15 – INFO – Device connected in flash mode
    27/053/2014 23:53:31 – INFO – Device disconnected
    Any ideas about it?
    Thanks in advance

  4. hey i have an xperia u without root and locked bootloader and usb debbuging is not enabled and the is crashed i don’t know what happend but when i turn it on the sony logo appear and re-appear again and the system is not booting , please help me what i should do and is that will fix the problem ? please reply as soon as possible thank you

  5. Thanks for this guide. All works great. I had problem with flashing, but it was about turning on Debbuging mode. It must be enabled.

  6. Hi.I installed cyanogenmod and my mobile get many bugs…so ineed to remove it and i have to install 6.1.1.B.1.89 Firmware,…so please help me to install 6.1.1.B.1.89 in my mobile….

  7. could i install kitkat 4.4 with the same method…….if yes plz give me the link to download kitkat 4.4

  8. I think by turning background process limt to 2
    or 3 will solve the problem mine is working flawless….. Thanks Mod

  9. Hey MOD!
    I have received Sony update 6.1.1.B.1.89..
    My phone is already updated on this as i did flashing..
    So, should I again update my software through Sony update service or not??

    1. Some apps may not be compatible with gingerbread, not games but some newly developed apps such as Vine and BBM are only compatible with ICS 4.0 and above. Since you are a gaming person we’d highly recommend staying on Gingerbread because ICS has many bugs and poor RAM management which will slow down your phones performance. :)
      Hope we’ve helped. If you need anything else, feel free to post a comment or fill in the Contact Us Form and we’ll get back to you ASAP.

    1. This firmware does tend to consume a lot of RAM, hence the lag in animations and overall performance. If you find it too slow, you could flash back to GB using the same method.

  10. Hi, I’m facing problem downloading the firmware from the link provided in this guide. When the download started the file was of 402MB approx but when the downloading was completed file size was just 250MB:-/ it was downloading smoothly but suddenly jumped from 63% to 100%. What should I do now? I tried this twice but result is same

      1. Yea I tried twice. But now I updated my xperia u via pc companion to ics 6.1.1.b.1.54 its running good with some lags. If u can give any other link to download the latest firmware i’ll be grateful. Thanks

  11. i just brought this phone.i’m pretty cnfused on upgrading it to ics..i have been to xda developrs thread but all of them r fornrs..shd i upgrade it to ics?

  12. Thank you so much Mod for helping..:)
    & i have a question also that For reverting back I have to remove firmware content from flashtool n place GB ftf. file in firmware like i did when i was updating..??

    1. It’s optional, if you remove it it’ll be more convenient for you. If you let it remain in the Flashtool/Firmware folder, it will ask you which .ftf you would like to flash and in that window you must choose the GB .ftf and NOT the ICS .ftf file.

  13. Hey.. Is this unbranded firmware safe?? I mean is it safe to flash my Xperia U back to this unbranded GB firmware?? give me your opinion Mod.. n can’t I get back to original GB firmware which was pre installed by Sony??

    1. This unbranded firmware is completely safe. The firmware provided in the link is the same GB Firmware pre-installed by Sony.

  14. Whether warranty will be voided if I am updating my firmware?.Can I revert back to present firmware using PC companion after flashing?

    1. No, warranty will not be voided if you update your firmware. If you want to revert back to Gingerbread (Oringial Firmware) here is the link to download it and you may flash it the same way as you flash ICS. http://d-h.st/Ug3

  15. My current Build no is 6.1.1.B.1.10 ICS and its laggy most of the time. Sometimes even I cnt pickup any phone due to its lag. Its really irritating. Does upgrading it to 6.1.1.B.1.89 solve my problem ?
    Also, how to do my phone backup so that everything (that’s in my phone including the games data and progress that I’ve made) can be backed up so that I can restore them after urgrading ?

    Please help. !!

    1. Thank you for the reply .
      Actually my phone is lagging evrytime I use my phone. Even my phone rings after 20 seconds during an incoming call. Also, Whatever application I use, whether it will be messaging or contact directory, it takes time and also hangs. At last I have to remove my phone battery to restart my phone. All this problems have been started after upgrading my Phone to ICS. So, I’m thinking whether upgrading its firmware to 89 or 100 will resolve this lag issue and also if this upgradation swipe out all my phone memory ??

      Please help !!

      1. Upgrading to v100 may not solve the problem since this lag issue is faced in all official ICS builds for Xperia U.

        If you’d like, we’d suggest flashing back to Gingerbread as it is more stable and it reduces lag.

      2. Ok , I got it.

        So, Is there anyway to root the phone ?
        If yes, then please tell me how to do it and also if this rooting of phone will harm my phone in any way (whether in void of warranty or any other issue).

        Thanks !

      3. Ok, Also please tell me that whether flashing back to Gingerbread will swipe all my phone’s data ? and also the games progresses on my phone ?

        If yes, then Is there any way to backup all the data alongwith the progresses ?

        Please help !!

      4. Only apps will be removed. App progress and data will also be wiped.

        Apps and App Data can not be backed up if the phone is not rooted.

  16. Hey mod.. after flashing the device works pretty slow.. i also replaced stock launcher with nova but it didn’t helped.. the messages are shown by a lag of 5-10 seconds.. and available ram is reduced to 20-25mb.. what should i do now??

    1. This is a problem faced by all Xperia U users, if the lag is unbearable you can always flash back to Gingerbread 2.3.7 by downloading the .ftf file. If you want to stay on ICS, you can download Advanced Task Killer and Memory Booster and set them to Kill Apps every 30 minutes/1 hour/2 hours according to your choice.

  17. and while downloading flashtool.. my antivirus detected a suspicious file(Win32:Evo-gen[susp]…..C:\Flashtool\x10flasher_lib ) and this was moved to chest.. should i proceed flashing anyway? plz reply

    1. Do not worry. It’s a false alarm. You may proceed with flashing, as for your previous comment yes it’s perfectly normal that it shows 402 MB.

    1. Re-install the drivers for the following:
      -Xperia U

      The drivers are located in this path:

  18. i just updated my xperia u to ics (6.1.1.b.1.10) and got a wifi problem, the phone gets the access to internet using wifi but after sometime it remains connected but the internet access is lost, what should i do, downgrade back to gb or upgrade to (6.1.1.b.1.89) ???

    1. Your current ICS Version (i.e 6.1.1.B.1.10) has many bugs, we’d suggest you follow our guide and upgrade to ICS 6.1.1.B.1.89 which fixes the Wi-Fi problem.

  19. thanks for tutorial. Kindly let me know can i downgrade again to gingerbread by restoring factory ? Thanks

    1. By restoring factory settings you will remain on ICS.

      You have to download the Gingerbread (2.3.7) ftf and flash it exactly the same way as ICS.

  20. Is this frameware in italian language? if yes then how to change in english and , it works on our GSM sims?

      1. I saw on sony support forum and they tick exclude ta as well,it is necessary or not?plz reply fast I’ll flashing it today thanx

      2. No it’s not necessary.
        Do not tick any unnecessary options or you may damage your phone.

      3. oops before your reply I ticked exclude ta and flashed it and now i’m on ics.Great experience ui,faceunlock,walkman and others are also great features but little lag.You also use this kernel, so you know how to remove lag?thnaks for your help

      4. If you are facing lag do the following:
        – Replace stock launcher with Nova Launcher from Play Store.
        – Go to settings – development – Transition scale – set to 0x.
        – Settings – development – Animation window scale – set to 0x.

    1. Please mention the error that you get in the Flashtool log.
      Re-install drivers for the following:
      Xperia U
      Flashmode drivers
      Fastboot drivers
      It should flash normally and your phone will boot into the new Stock ICS Firmware.

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