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first time flash my phone abit scary =.= '''''' thx for all the help from Garret 14 uliwooly and thommo >.< hope it will success
Anytime
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many error come out after the flash =.= '''' it show the process android, process,acore has stopped unexpectedly please try again ...... and the process android.process.media has stopped unexpectedly please try again ... wat happend T_T
I take it you downgraded from ICS to GB and if you did - did you leave the box ticked to wipe data if not then as I did you will get these problems and error and force close pop ups - All I did was backup what I wantwed to keep and leave or tick the box wipe data and then flash, Problem solved it will not wipe your SD data ie music photo's but thats not to say that it won't
repair it with SUS
Update Service (SUS)
http://www.sonymobile.com/gb/tools/update-service/
http://www-support-downloads.sonymobile.com/Software%20Downloads/Update_Service_Setup-2.11.12.5.exe
Alternatives on How to backup Xperias
http://talk.sonymobile.com/thread/36355
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I know of a guaranteed way, but it will void your warranty. Go to forum.xda-developers.com, search for your phone, follow guides to root your phone, then find a Shipped Sony LT26i/Xperia S Rom and flash it.
thx for everyone help ....... after i master reset everything in the phone , the error never pop up again ==....... i think next time flash a phone must backup everything , contact , msg , apps , etc then should be no proplem =X .... finally i know how to flash a phone T_T ,,,thanks everyone for helping me
Anytime, enjoy your phone and flashaway 
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