Constraints on singularity resolution by nonlinear electrodynamics

One of the long standing problems is a quest for regular black hole solutions, in which resolution spacetime singularity has been achieved by some physically reasonable, classical field, before one resorts to quantum gravity. The prospect using nonlinear electromagnetic fields this goal limited Bronnikov's no-go theorems, focused on Lagrangians depending invariant $F_{ab}F^{ab}$ only. We extend results taking into account that depend both invariants, and $F_{ab}\,{\star F^{ab}}$, prove tension between Lagrangian's Maxwellian weak field limit boundedness curvature invariants persists more general class theories.