Seems to me that main difference is that with PinePhone and FLOSS we can see such issue. It is hard to say how many non-free phones have similar hacks. Considering the usual state of embedded software, i would guess that many.
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.
Radios are much more regulated.
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.