Just in case this helps someone..
I was trying to flash my Naze32 rev5 with Cleanflight and after a while the board seemed to be bricked! Without jumpering the boot pads, it would power up with a solid blue led (like when you jumper the boot pads!). Cleanflight wouldn't flash on connect and it wouldn't respond at all.
So... I powered everything off, then set up Cleanflight to flash on connect again and then with a lot of pressure I pressed my jumper pin across the boot pads and plugged in to the USB... and it flashed!
Those boot pads can be a pain to short - try pressing really hard (or clean them first)!