[Need help] Extreme Xperia SP brick with start loop

Hi guys!! This is the worst brick I've had.

• I can't use the flashmode more than ~10 seconds cause it randomly disconnects


• I CAN use the 3 recoveries already installed TWRP, PhilZ and CWM


• I tried with Linux and diferent Windows drivers


• I'm runing the flashtool 0.9.19.0 version


• I have this rom installed http://forum.xda-developers.com/xper...users-t2868398 by MrSteve555

I'd like to reinstall the base ROM 4.3 Movistar/Spain I got the "ftf" file.