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
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?