Thanks.That is how I did it.
Flash .307 , root it with v17, update supersu, make it system (needed 2 times, 2 restarts), ota. 244 and still have root.
Just perfect.
Sent from my SGP321 using xda app-developers app
So how do I make super subject system?, How did you know you had to 2 times and have 2 restarts?
Can it be unroofed if I have problems and need to ship back to Sony in the future?