Photon is not connecting to the cloud - breathing green after cyan breathing for 2 second

[ScruffR]

That would indicate that the bootloader got wiped and recovering from that requires extra hardware.
Have you got anonther Photon or a JTAG/SWD programmer?

With another Photon you could try this

How to recover photon with only dim blue LED on D7 [Solved]

I have looked through the other threads from last year and have tried all the suggested approaches to get into dfu-util mode but none works. I believe that the 2 photons I have which are in this state were loaded with system firmware 0.6.2. They have been operating normally when removed from their circuit board to be upgraded. Any hacks to get these 2 talking.

If that is no option you could file a support ticket at support.particle.io and explain how your device got into that state.