I am having the same SOS Hard fault on both of my photons running 0.4.6 and just Tinker – no pins connected to anything. Often when I move my body near the photons, I’ll see a combination of flashing green WiFi drop (even though I’m well within WiFi range), sometimes a recovery back to breathing cyan, and/or an SOS hard fault – in various orders. Sometimes the hard fault comes first. Very strange. The Photons can go hours without having the problem and then, usually precipitated by nearby movement (I assume WiFi signal fluctuation), exhibit this problem.
I discovered that if I switch over to another WiFi router, then this problem disappears completely. The one that works is an aging Linksys WAP54G and the one that correlates with failure is a modern and common Netgear WNR1000.
Now, I understand that there can be compatibility issues between network devices. However, my laptop, iPhone & iPad don’t crash & reboot when encountering WiFi problems. It’s highly desirable that my Particle based product remains stable when encountering signal disturbance.