[Solved]: Unable to Flash Spark Core Error: "Request Timed Out"

[ScruffR]

@agard, you already have an own thread for this, so please don't open a new discussion, especially since this thread deals with a Spark Core and not a Photon.

Photon breathing cyan but shows offline in CLI, flash timeout

There is no factory reset on the Photon. This "success" report is not to be trusted, you can throw any .binfile (even a pure text file) at the device with that command and you will always get a success. Rather try particle flash --usb firmware.bin in DFU Mode (blinking yellow). That indicates you are not targetting the correct devices. In Particle Build you will find a SIGNAL button under your device details to check wheter or not you are actually targetting the correct device. If you ar…