After the many updates to the optimus F3, My sister was unable to use her phone because of a lack of space. She allowed to attempt to root it, I was unsuccessful the first couple times. However, I found a new root method working for (at least) the T-mobile version of the Optimus F3! Download Bin4ry root from here xda-developers thread =1886460 And then run the Runme.bat file, use 0 ( Xperia root method) everything will do its thing and then the phone will reboot and all you have to do is install the SuperSU binary and you have root! If this does not work, try doing a factory reset and then following the process again.