I'm new to Sony Devices and bough the US Lte version recently and started exploring it.. These are my finding related to SGP351, if anything mistakenly added, please let me know i will correct it..
Here is the Android 4.3 Update for SGP351 (US Lte Variant)...
*Root available for 4.3 XTZ now..
Here is the Android 4.1.2 for SGP351
FLASH AT YOUR OWN RISK
If you have flashed 4.3 and want to go back follow this
How to Flash
Use the Latest Flashtool (http://www.flashtool.net/index.php)
download and copy of the FTF file under Firware folder in Flashtool installed directory.
Click the Flash Icon in Flashtool, Select the Flash Mode and select the Firmware to flash it.
How to Root?
Currently Works only in SGP351, 4.1.2 version
1. Flash the 4.1.2 Version.
1a. Make sure USB Debugging and Unknown sources installation checked under Settings in XTZ
2. Install the Vroot from the site (DoomLord exploit will not work in SGP351 version)
3. It will identify your device, click the green icon on the bottom-left.
4. it will ask you for ADB authorizes in Tablet, select always tick mark and click ok.
5. Install the Root and reboot.. (additional Chinese market app will also be installed, you can uninstall later.)
6. Now you need to Install Reboot Fix from @[NUT] files(as the System R/W will not work properly) and follow the instructions
7. if no errors, your tablet is ready and rooted
8. if you want install the Super Su from market, get root access. and remove the Chinese Super User.
if you want to move to Custom Roms, from 4.3 or 4.1.2 version backup the TA partion
[COLOR="rgb(255, 140, 0)"]Backup the TA[/COLOR]
Once rooted (follow the above steps), backup your TA partition which will have all the information related to Sony's Bravia Engine,,
Use the below TA Backup by @DevShaft
Now Unlock your Bootloader to Install the Custome CM/AOKP Roms if needed. and want to come back to Stock.. restore the TA backup to use your Bravia/Sony Sound Mods
All the Dev/Contributors & User of XDA