For the Belle II spectrometer a proximity focusing RICH counter with an aerogel radiator (ARICH) will be employed as a PID system in the forward end-cap region of the spectrometer. The detector will provide about 4$\sigma$ separation of pions and kaons up to momenta of 3.5 GeV/$c$, at the kinematic limits of the experiment. We present the up-to-date status of the ARICH simulation and reconstruction software, focusing on the recent improvements of the reconstruction algorithms and detector description in the Geant4 simulation. The effect of these on the detector performance is studied using the full Belle II detector simulation and the results of these studies will be presented. In addition, we will show the first reconstructed Cherenkov rings that will be collected during the detector cosmic-ray test, which is foreseen to start in the early summer. The analysis of these data will allow for the test of our full reconstruction chain, as well as for the validation of the Geant4 simulation, through the comparison of the measured and Monte Carlo data.