Are there safety regulations or certifications for this? If so do smartphones usually pass them and does PinePhone pass them?

There are an enormous number of regulations around this, if you look at all the regulatory markings on most electronics. UL and Intertek being the biggest ones for electrical safety. I really hope Pine64 has gotten those certifications.

AFAIK one of the reasons phones typically leave logic like this in a binary blob on an IC is because the certification bodies stipulate that not only does a device have to comply with safety standards, but it can't be trivially modifiable by an end-user to violate those standards.

If you're marketing a phone where one of the advertised features is the ability to change the operating system, and the operating system is responsible for enforcing electrical safety, i don't really see how that's certifiable.

That's usually for radio emissions, not for stuff like thermals.

Radios are much more regulated.

This is the Pinephone's CE certificate:

http://files.pine64.org/doc/cert/PinePhone%20CE%20RED%20Cert...

Would be fun to see what of those articles are safety related, and what do testers test for actually.

I wonder, if pinephone were to sell a version that was an ikea-style assemble-it-yourself kit, would that still require those certifications?

CE and CCC are the most important as they cover Europe and China.