The first inflationary model conceived was the one proposed by Starobinsky which includes an additional term quadratic in the Ricci-scalar R in the Einstein–Hilbert action. The model is now considered a target for several future cosmic microwave background experiments given its compatibility with current observational data. In this paper, we analyse the robustness of the Starobinsky inflation by inserting it into a generalized scenario based on a -Starobinsky inflation potential, which is motivated through brane inflation. In the Einstein frame, the generalized model recovers the original model for , whereas represents an extended class of models that admit a wider range of solutions. We investigate limits on from current cosmic microwave background and baryonic acoustic oscillation data and find that only a small deviation from the original scenario is allowed, ( C.L.), which is fully compatible with zero and confirms the robustness of the Starobinsky inflationary model in light of current observations.