If you updated your Sony Xperia SP to the latest firmware 12.0.A.2.254 firmware and you have worried due to losing of the root access, just follow this tutorial. This method helps you to re-gain root-access on your device.
By following this procedure the warranty of your phone gets void, so make sure before you have rooted your phone.
1.Make sure your Sony Xperia SP phone was running on firmware version 12.0.A.2.254.
2.You should backup all your internal data’s before rooting, so then it will be safe. If anything goes wrong, you can get them back with the help of backup.
3.Next charge your phone fully, it helps to avoid the power issues.
Procedure to root Sony Xperia SP smartphone:
1.Open the Flashtool and flash the same.
2.After that reboot your phone and connect to the computer in USB debugging mode.
3.Then close the flashtool. This step is very important so don’t neglect this step.
4.After that download and extract the DooMLoRd rooting toolkit to root directory on C:\
5.Next execute runme file and follow the instructions.
runme_linux.sh for linux
runme_mac.sh for mac
runme_win.bat for windows
6.Once the process is finished, your device will reboot.
7.After that power off your phone and launch the Flashtool again.
8.Now flash this file. It is the latest kernel from 12.0.A.2.254 firmware.
9.Power On your phone, now your phone must be rooted.
10.Congrats! And enjoy with your rooted phone.