The topic pretty much says it all. This isn’t a huge deal due to the low cost of the Photon but I’m curious. Thanks!
I was hoping I didn’t have to answer that. It’s a long story but it was 9V.
@Silverminer, if only the buck regulator is damaged then you can replace it. An alternative is to supply the photon directly with 3.3v on the 3V3 pin, bypassing the regulator.