My core had been working fine. I have only used the tinker app and not loaded my own code. Changed location and so did a long press on the MODE button to reset to to factory so I could easily change wifi settings.
I didn’t get the slow blue flash during the long press, and also didn’t get the fast blue flash after 10 seconds. Flashing seemed to stop.
Now i get nothing. Pressing the reset button only see a light green (maybe its same as the yellow flash). But it only flashes 3 times, then nothing. I will work through the ‘only yellow flashing’ to see if that helps.