While being of great interest, measuring the topological susceptibility above the QCD critical temperature is twofold complicated. First, instantons transitions are expected to be suppressed. Then, as one approaches the continuum, the Monte-Carlo evolution tends to get stuck in a given topological sector. Whilst the first one is a physical effect, the second one is an algorithmical problem, often referred to as the topological freezing. A possible way out which was put forward is the use of open-boundary conditions, which supposedly improve the topological sampling. This type of boundary conditions has mostly been studied at $0$-temperature. The aim of this talk is to carry this discussion over above $T_c$.