Sean Carroll states the Einstein's Equivalence Principle (EEP) as "In small enough regions of spacetime, the laws of physics reduce to those of special relativity; it is impossible to detect the existence of a gravitational field by means of local experiments."
Local flatness theorem says that there exists a class of coordinate transformations such that any general metric can be brought into the Minkowskian form (special relativity form). So isn't a proof of the local flatness theorem is (almost) a proof of the EEP?