What are the kind of boot/init processes that require the RNG? Is it only a requirement on some systems, or does basically every gameboy, laptop, soda machine etc have init processes that would need the RNG?

The issue that triggered this revert, if I'm understanding it, was that RNG reads had to be minimally decent and non-blocking already in order for a certain system to seed the RNG.

This is definitely breakage, but it'd be interesting to know about the less "reflexive" applications.