Linear and nonlinear stability analyses of the entropy layer over a blunted plate are discussed. Results of the linear stability theory are compared with the direct numerical solution of the Euler equations when a disturbance of prescribed frequency is imposed on the mean flow. A solver of the Euler equations based on the Space-Time CE/SE method predicts linear and nonlinear dynamics of unstable disturbances with high accuracy. A relatively coarse grid allows for simulation of nonlinear disturbances with the mass-flux amplitude up to 9%. The nonlinear effect demonstrates a trend to saturation of the entropy layer disturbances.