My photon was working just fine and then suddenly stopped responding. D7 is lit dimly blue. It won’t respond to flashing, and it won’t enter DFU mode. I’ve tried wiring D7 to ground per advice given in a different thread, but nothing doing. D7 stays blue no matter whether the photon is connected to a battery pack or my PC. What do I do? Is my photon dead? Thanks in advance for your advice.