Default xperia go os erased

I erase my system by using the fastboot command " erase system -w " and flash a kernel in this topic http://forum.xda-developers.com/xper...3-184-t1888247 and reboot ! now my phone don't connect to the PC it appear unknown device and can't use fastboot again and all that appear on the screen is Sony "under it " custom

is there any hope ?!