@eschwartz: Yup. Note that it tripped MRPI because I made the same kind of check mntroot does, but as a blocker, while mtnroot will silently think it doesn't need to do anything, and thus leave the rootfs rw
.
I'll switch MRPI to a more robust method, but that still leaves this open to anyone who might be using mntroot (granted, switching the rootfs rw is a terrible idea in the first place, but, still, in certain circumstances, it's unavoidable, and mntroot is nice to have and use without reinventing the wheel
).