For the flatness analysis, generalized Jacobians are used, whose entries represent noncommutative Ore polynomials. Based on a generalization of the inverse function theorem for dynamical systems, a well-known flatness condition is reclassified, and a tool for its verification is presented. Supported by examples, this perspective reveals weaknesses in the condition which are discussed. Nevertheless, the approach remains useful for determining flat outputs. The procedure is described and transferred to the computation of flat inputs.