First attempt to root.......Please help....!

[Xperia80]

I have a xperia u (ICS 4.0.4) after update to the ICS my phone lags a lot and very slow.So i thought i should flash a JB(4.1 or 4.2) rom.I didn`t do it ,because JB roms have major bugs(camera not working).Soi am happy to stick with ICS.If you know any stable jelly ben rom please tell me.I found that xperia u, firmware version 6.1.1.b.1.100 is more smooth and less bugs ,but it`s not availbale to update via pc companion ,I am sorry that i ask previously ask questions ,i saw a uliwooly`s page about upgrading but  i don`t undstand that becaue this is my first attempt.please answer my questions.My English not good, sorry for that.this is like a exam paper  ,Thank you

current staus------------------>
Sony Xperia U (ST25i)
ICS 4.0.4
Firmware 6.1.1.b.1.54
        (Qustion look simillar but read whole question,put the question number and answer,because it easy to undstand)

1) how to find my phone root or unlocked bootloader(because i buy it from a friend) ?
2) Do i need to unlock my bootloader to flash a new firmware version ?
3) Do i need to unlock my bootloader to install a JB(4.1 or 4....) rom ?
4) what is the most smooth and lees bug sony firmware for xperia u (i found that it is 6.1.1.b.1.100 ,http://www.xperiablog.net/2013/06/22/new-firmware-released-for-xperia-u-6-1-1-b-1-100/) ?

5) Do you know any jelly bean rom for xperia u which is stable and no major bugs ?
6) Can i use sony flash tool to flash my phone (http://developer.sonymobile.com/services/flash-tool/) ?
7) After i flash my phone ,if sony release a new update can i install it via pc companion ?
😎 After unlock the bootloader,,if sony release a new update can i install it via pc companion ?
9) After i flash a new Firmware ,If i want to go back to old firmware ,can i do that ?  

10) After i flash a new Firmware ,If i want to go back to old firmware ,can i do that ?
11) After i flash a Jelly bean rom ,If i want to go back ICS (firmware 6.1.1.b.1.54 ) ,can i do that ?
12) Can i unroot ? can i locked my bootloader if i unlocked ?

[Uliwooly]

1. 2. you don't have to unlock the bootloader to neither flash your phone nor root your phone 

3. yes

4. GB its a lot more stable than ICS

5. check the XDA forum

6. 

How to manually update, downgrade, root 2012 Xperias

http://talk.sonymobile.com/thread/41609

7. if you unlock the bootloader you won't, otherwise you will

8. you will have to relock the bootloader BUT your DRM keys will be gone forever

9. 10. check 6.

11. you have to relock the bootloader then flash back but your DRM keys will be gone

12. yes, you can root with PCC or SUS, you can't use PCC nor SUS with an unlocked bootloader

[Xperia80]

wow thanks,but how do i know i my phone was root ? & unlocked the bootloader ? and can you pleas explain 8 to 12 answers explain bit more,i mean more detaily.....!

[Uliwooly]

if your bootloader its unlocked you can NOT use PCC nor SUS, it will say that you have modified software, to test if you have root access simple, install any app that require root access such as root explorer or barnacle tethering, etc. 

[Uliwooly]

Update Service (SUS)

PC Companion (PCC)

Bridge (for Mac)

Alternatives on How to backup Xperias

http://talk.sonymobile.com/thread/36355

[devsatan]

1) You can find whether you phone's bootloader was unlocked or not by simply dialing *#*#7378423#*#* Then go to service info >> Configuration ANd see what's the staus of Bootloader.

2) No, you dont need to unlock your bootloader to flash either ICS or Gingerbread. 

3) Yes, If you are installing  a custom rom auch as Cyanogen Mod or Custom jelly bean rom  ,then you should unlock your bootloader.

4 , 5) Yes according to me this is the most stable version of ICS. but I did like to prefer to use Jelly bean rom by Devswift as it is fully stable with no bugs.

6) Yes, Flashtool is the only tool that works with sony phones to flash a .FTF file which is a firmware file for all sony phones.

7) It depends on whether you have installed a regional firmware or some other operators firmwares.

11) Yes you can simply go back to previous version of ICS or Gingerbread but you should do it in a right way otherwise you will brick your phone.

[anfer66]

i ask the question(xperia 80 is me) but,after sign out i unable to sing in so use a different account.
you informationa are very helpful,but please can you tell me how to find the  Devswift JB rom,how to download it ? and can you keep in touch with this discussion ?

[devsatan]

Yes sure. I will tell you the whole procedure how to do safely do it . 

And don't forget to give kudos and to select the correct answer.

[Uliwooly]

It's not wise to share private info, its better to post everything here as other users might want to know

[anfer66]

i am soory,uliwooly is right,their is no need of private discussion,you can post all the information here,.....!