I am having troubles. My Xperia Play won't boot into flash mode. USB debugging is on, phone is in MSC mode. I turn the phone off, press the back button while plugging in the USB cable and it boots into fastboot. (Blue LED light turns on and Flashtool recognises it as Fastboot mode). I am running DooMKernel and Ice-Cream SONY rom, but have tried changing ROMs and that doesnt affect it.