I have the same HW Z23L and after shooting 2k at 35Mbit for 10 minutes with wifi and android app on, I was disconnected and the camera froze. The led ring led was set to off prior to this. The only thing that it did when I powered it on was a short blink of the top red led (maybe the others too, I didn't notice) and then froze again just after I pressed power button again or wifi. Though when I pressed wifi button it light up and then it froze. I led it cool down after some attempts, removed the sd card, the battery, pressed the buttons but still no change. After that I connected it to the pc via another standard micro usb cable ( I am not using the cable provided). First mass storage was not detected. After another attempt it went into storage mode. After that it worked fine. I am feeling a bit confused. A tried also shooting with 1080p 60fps 35mbit, also with 720p 120fps 35 mbit, although not that long (5min.) Maybe the camera doesn t cope with wifi streaming and high bitrate at high rez. More tests to be done!