I had this issue on same car in which it took me a entire day to flash ecu 5 times. I ended up disconnectring battery in which helped this one time after many attempts as i think it somehow spazzed the icm out during write. I also tried a different laptops and usb cables to see if it improved.
Make sure your headlights are off and remove interior light globe if it is on as they seem extremely senstive to voltage fluctations.