Can't flash electron over USB

I was able to flash over USB in Particle dev one time, then it stopped working. I’m getting a serial connection in dev, so I know the device is there. The electron is breathing blue, red battery charge light is on.

I’ve tried restarting all devices and switching the USB port.

It still only offers to flash via cellular. Flashing via cellular works, but seems very unreliable. Half of the time it gets stuck in a cycle of flashing after an attempted flash.

Huh :confused:

I’ve never seen an option for USB flashing in Dev?
I use CLI particle flash --usb firmware.bin

I think you are correct. I misunderstood the directions. I’m trying to get CLI working now.