Although the 0 K phonons reasonably describe the lattice dynamics of many materials, they break down for materials with imaginary frequencies (unstable phonon modes). Such dynamical instability occurs when the harmonic potential is inverted in certain vibrational directions. Materials with dynamical instability can only manifest in practice if the temperature is high enough to increase atomic displacements beyond the inverted harmonic region, at which point the system can be stabilized by anharmonic potentials. This high-temperature lattice dynamics can yield effective harmonic phonons that are fully real to the indication of dynamical stability. In this workflow, we adopt a renormalization procedure using 4th-order anharmonic force constants to efficiently implement finite-temperature phonon calculations. This method's advantage lies in not requiring any additional DFT calculations beyond those for the initial fitting for harmonic and anharmonic force constants. A detailed explanation of the renormalization step is provided in the Methods section.