Respeaker Core V1.0 total factory reset, how do I do it?

Power should be ok, card is Sandisk Ultra.

What can I post a link to ? The sketch is here respeaker_arduino_library/examples/pixels_pattern/pixels_pattern.ino at master · respeaker/respeaker_arduino_library · GitHub

I have been trying to get my head around extroot to undo the overlay process but all documentation that I have found is all about doing, there is precious little about undoing…

Thanks for the reply by the way.