Try plugging the micro usb end of your data cable into your phone with the other end unplugged, then press and hold the 1 button (on physical keyboard) and the power button at the same time and hold while plugging the USB end into your pc. Yeah, I know you only have two hands but it's not like juggling or anything. lol. I believe this should "trick" the device back into download mode. There are threads out there addressing this very issue, if you did some more browsing you'd find more info but I believe this was the method that I had to use when I was in the same situation you are now. Good luck.