I see. Thank you for the insight!

No, the app is running on an iPhone I'm afraid, not Intel, that's why I'm so confused about SIGILL. I was able to post a crash report in a separate reply.

Yeah, I get that it's an illegal instructions, but I don't quite understand why exactly it happens and why it's not something like EXC_BREAKPOINT (SIGTRAP) or EXC_BAD_INSTRUCTION (SIGILL) or why this particular code is missing from the documentation. Investigating the accessibility of the data store is a great idea, but unfortunately I couldn't reproduce the crash myself, so I guess it's fully accessible most of the times.