Mine did the exact same thing. I am sending my back also. Geen LED on the Camera and picture, but no LEDs on the HThe ST16 update went fine, but the OTA update of my H went wrong three times (timeouts and http connection failed...). In the end I was unable to turn the H off as it seems to got stuck in the firmware update process.
After a while I disconnected the battery and now when pushing the "on button" there is no sound and only the camera connects to the ST16. I tried to update the H via SD card inside the CGO3P and via USB cable with the PC TyphoonHGUI but both to no avail.
I now got a half dead H that doesn't start up anymore. I will have to call Yuneec on Monday morning.