I am trying to get the Device ID of a Photon through the SWD interface (I couldn’t get JTAG to work). I am in J-Link Commander and trying to read the memory location 0x800473C for 6 bytes as follows:
The field labeled "device id" in the DCT is probably not the device ID you're thinking of. The device ID used by the Particle cloud is the STM32F device ID, and you can get it this way via JTAG/SWD: