Electron breathing white - how to get to listening mode?

General
1

I am trying to use the HX711 with my Electron board and I got to a point where I have “breathing white” - which I believe means that the cellular mode is off.
I would like to upload a new firmware via USB, which requires listening mode (flashing blue), but even if I hold the MODE button for 3 seconds it never enters listening mode, it is either steady white or breathing white, nothing else.

Any idea how to get to listening mode from white?

2

Can it be placed in DFU mode?

3

Thanks, that did help to get out of the steady white / flashing white cicle.