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[Q] C6903 .290 Need help with root, downgrade, TA backup

23rd January 2014, 09:09 AM   |  #1  
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Alrighty some background info and where I'm at. I've got some dev (Android XML layout fixes) experience on a custom ROM on i9300 and I finally decided to upgrade my phone onto the beasty Xperia Z1.

My phone came factory shipped with .290. It's the C6903 model. I've been looking up videos and trying to find info about where to begin with getting my root, bootloader, cwm, and custom ROM install going. Then I found out about the TA partition and that even though my phone allows me to unlock the bootloader, it's a smart idea to first backup the TA partition before I unlock my bootloader via the $ony website. With the TA backed up I can revert my phone back to stock at some point and restore the TA so that my phone looks basically factory fresh. So I realised that I probably ought to back up my TA in case of any warranty issues. Which means I need to get my phone rooted before anything else. (I hope my assessment has been correct so far, it would be awesome if someone can verify the above paragraph)

Now this is where I am completely confused. I've attempted to use VRoot - and of course it does not support the .290 firmware.

Then I found out that it is possible to downgrade the firmware so that I can root and TA backup before bootloader unlock. This is the knowledge level I am up to. I have no idea which firmware to downgrade to or how to even actually perform a successful downgrade. (I've kinda gotten frustrated at the huge slab of info and I need some specific info from some users more experienced at this than I am at this point..)

I read how some people have flashed down to .534 and others have flashed down to .257. I would like to know exactly what steps I should take and which is the best firmware to downgrade to, just to do a root crack and TA backup. Can you even downgrade firmware without bootloader involved?

Basically the flow of what I need to do right now is this (I think):

1) Downgrade firmware to probably .534 from my current .290 (I need to flash the FTF using Flashtool, correct?)
2) Install Root with VRoot
3) TA Backup (http://forum.xda-developers.com/show...8&highlight=ta)
4) Upgrade back to .290 (Do I do this via OTA? I hope it is not difficult to do it via some command line tools if it comes to that..)
--- Above step also gets rid of most of Root access provided to the older firmware (this is what I've read.. Is this correct?)
5) Unlock bootloader (must do this in version .290 to avoid the camera bug), via guide on Sony website
6) Go crazy with all the custom things I want to install - CWMRecovery, CM11, etc
7) ???
8) Profit

Can someone please tell me if the above list is the order I need to proceed with?

Thanks for any help you guys can give me. I am truly frustrated by this 290 firmware version! And reading all the topics about people who bricked after attempting similar things without knowing exactly what they needed to do and which order to do it in..

tl;dr - On .290 firmware, I want to backup TA before I unlock bootloader, which firmware version do I downgrade to?
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23rd January 2014, 09:36 AM   |  #2  
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Quote:
Originally Posted by SleepinDevil

Alrighty some background info and where I'm at. I've got some dev (Android XML layout fixes) experience on a custom ROM on i9300 and I finally decided to upgrade my phone onto the beasty Xperia Z1.

My phone came factory shipped with .290. It's the C6903 model. I've been looking up videos and trying to find info about where to begin with getting my root, bootloader, cwm, and custom ROM install going. Then I found out about the TA partition and that even though my phone allows me to unlock the bootloader, it's a smart idea to first backup the TA partition before I unlock my bootloader via the $ony website. With the TA backed up I can revert my phone back to stock at some point and restore the TA so that my phone looks basically factory fresh. So I realised that I probably ought to back up my TA in case of any warranty issues. Which means I need to get my phone rooted before anything else. (I hope my assessment has been correct so far, it would be awesome if someone can verify the above paragraph)

Now this is where I am completely confused. I've attempted to use VRoot - and of course it does not support the .290 firmware.

Then I found out that it is possible to downgrade the firmware so that I can root and TA backup before bootloader unlock. This is the knowledge level I am up to. I have no idea which firmware to downgrade to or how to even actually perform a successful downgrade. (I've kinda gotten frustrated at the huge slab of info and I need some specific info from some users more experienced at this than I am at this point..)

I read how some people have flashed down to .534 and others have flashed down to .257. I would like to know exactly what steps I should take and which is the best firmware to downgrade to, just to do a root crack and TA backup. Can you even downgrade firmware without bootloader involved?

Basically the flow of what I need to do right now is this (I think):

1) Downgrade firmware to probably .534 from my current .290 (I need to flash the FTF using Flashtool, correct?)
2) Install Root with VRoot
3) TA Backup (http://forum.xda-developers.com/show...8&highlight=ta)
4) Upgrade back to .290 (Do I do this via OTA? I hope it is not difficult to do it via some command line tools if it comes to that..)
--- Above step also gets rid of most of Root access provided to the older firmware (this is what I've read.. Is this correct?)
5) Unlock bootloader (must do this in version .290 to avoid the camera bug), via guide on Sony website
6) Go crazy with all the custom things I want to install - CWMRecovery, CM11, etc
7) ???
8) Profit

Can someone please tell me if the above list is the order I need to proceed with?

Thanks for any help you guys can give me. I am truly frustrated by this 290 firmware version! And reading all the topics about people who bricked after attempting similar things without knowing exactly what they needed to do and which order to do it in..

tl;dr - On .290 firmware, I want to backup TA before I unlock bootloader, which firmware version do I downgrade to?

Yes, you need to downgrade to .534 and root before you can backup your TA

Here is a guide on how to achieve that


If you follow the video guide you will end up with rooted .290

Then backup you TA:


and go to Sony's website to unlock the bootloader. An unlocked bootloader will let you flash custom kernels to your phone and thus you will be able to use roms such as CM, AOSP etc.


NEXT TIME PLEASE READ BEFORE CREATING A NEW THREAD. THIS HAS BEEN COVERED 100's OF TIMES
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23rd January 2014, 09:47 AM   |  #3  
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in general you have to do these steps:

downgrade to an early firmware that can be rooted and root it.
then install dual recovery.
in dual recovery wipe your phone, flash rom, flash again superuser and again dual recovery.
power off phone.
power on and direct flash kernel,baseband, bootbundle. for this i would recommend using NUTs stripped FTF files. also from his site you get recovery and superuser/supersu.

you only loose TA when you unlock your bootloader. unlocking is only neccessary if you plan to flash a custom kernel too.
when you are on rooted firmware backup TA, you never know if you need it later.

a good step by step tutorial is iHackers 2.1 thread.

also be prepared that actually there is a chance to brick your device. many can be restored using Sony Update Service or by flashing a full stock FTF, but some devices need a new mainboard. things are a litte bit tricky at the moment
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23rd January 2014, 11:46 AM   |  #4  
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Quote:
Originally Posted by shem2409

Yes, you need to downgrade to .534 and root before you can backup your TA

Here is a guide on how to achieve that


If you follow the video guide you will end up with rooted .290

Then backup you TA:


and go to Sony's website to unlock the bootloader. An unlocked bootloader will let you flash custom kernels to your phone and thus you will be able to use roms such as CM, AOSP etc.


NEXT TIME PLEASE READ BEFORE CREATING A NEW THREAD. THIS HAS BEEN COVERED 100's OF TIMES

When on 4.3 and I tried many time still can't downgraded to 534. How to do it? Thank!
Lukily my TA had been backup.

Send from GT-I9506 using Tapatalk
Devices: Samsung GT-I9506 and Sony Z1 C6903
Last edited by timberwolf60; 23rd January 2014 at 11:48 AM.
23rd January 2014, 11:51 AM   |  #5  
shem2409's Avatar
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Quote:
Originally Posted by timberwolf60

When on 4.3 and I tried many time still can't downgraded to 534. How to do it? Thank!
Lukily my TA had been backup.

Send from GT-I9506 using Tapatalk
Devices: Samsung GT-I9506 and Sony Z1 C6903



Here is a video on how to use flashtool
The previous video that I have sent you shows you step by step how to do everything
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