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In a recent paper [Phys. Rev. D{\bf 85}, 023528 (2012)] the authors proposeda generalized Born-Infeld electrodynamics coupled to general relativity whichproduces a nonsingular bouncing universe. For a magnetic universe the resultingcosmic evolution inevitably interpolates between asymptotic de Sitter states.Here we shall show that (i) the above theory does not have the standard weakfield Maxwell limit, (ii) a sudden curvature singularity -- not better than thebig bang -- arises, (iii) the speed of sound squared is a negative quantitysignaling instability against small perturbations of the background energydensity, and that (iv) the conclusion about the inevitability of the asymptoticvacuum regime in a magnetic universe is wrong.

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