[ROOT] Rooting Xperia SP

Guys this guide is same as DooMLoRD's guide but modified for the 12.0.A.2.254 firmware version for Xperia SP (C5302/3).

Follow these simple steps and get your sexy device rooted.

1. Open FlashTool and flash the XperiaSP_C530X_12.0.A.1.257_KernelOnly.ftf - 6.78 MB file.
2. Reboot your device and connect to PC in usb debuggin mode.
3. Close FlashTool. (important step)
4. Download and Extract DooMLoRD_Easy-Rooting-Toolkit_v18_perf-event-exploit.zip to root directory on C:\
5. Execute runme file(runme_linux.sh for linux, runme_mac.sh for mac and runme_win.bat for windows) and follow the instructions, in the end your device will be rebooted.
6. Hopefully you will be rooted now(You can check it by launching SuperSU app from the launcher).
7. Power off your device and launch FlashTool again.
8. Now flash XperiaSP_C530X_12.0.A.2.254_KernelOnly.ftf - 6.95 MB file.(Latest kernel from the 12.0.A.2.254 firmware).
9. Power on and enjoy rooted phone with latest firmware. 

If you are facing issue of device rebooting when remounting /system partition then checkout the fix posted by @[NUT]

All credit goes to DooMLoRD