Blue tile BCN002V1 won't enable

I've had intermittent success at flashing the firmware provided with the DK for the BlueNRG tile (STEVAL-BCN002V1) when attached to the host board. I can see the image file loading on to the device memory followed by a successful verify and sometimes the tile's blue light is on for pairing with the iPhone app. But lately the LED is solid green and doesn't seem to want to enable into BLE mode? I have two tiles and the device memory seems to match between the two and so i dare not touch the "good one". Any ideas as to what i'm doing or done wrong?

Thank