Do one thing.. Remove Battery, press power button for around 10-12 seconds.. Insert the battery and try to flash again using flashtool..
Nokia 5233 (At home)
Nokia 5230 (Broken Display)
Sony Xperia L (Stock 4.2.2, Rooted, 15.3.A.1.14)
Ex-Symbian Modder, new to Android world
Hit "THANKS" button, I appreciate it..