Large-mass bolometers are calorimeters working at low temperatures widely used in particle physics experiments to search for rare events. These devices are able to detect particles energies from few keV up to several MeV, but their response function is not linear and depends on the operating temperature. This study was performed with the bolometers of the CUORE experiment. In a previous work the non-linearities were attributed to the thermistor and to its biasing circuit and an algorithm was derived to obtain a linear response. In this work an improvement of the algorithm is proposed and the possibility of developing a more complete model of the response function, which accounts for the electrothermal feedback induced by the thermistor, is evaluated