Robots face the eventuality of falling. Unplanned events, external disturbances and technical failures may lead a robot to a condition where even an effective dynamic stabilization is not sufficient to maintain the equilibrium. Therefore, it is essential to equip robotic platforms with both active and passive fall protection means to minimize damages, and enable the recovery and restart without physical human intervention. This work introduces a method to design an integrated safety system for two-wheeled humanoids. As a case study, the method is applied to a robot and experimentally tested under several conditions corresponding to different causes of robot instability, such as motor jamming, external disturbances, and sudden shut-down.