1. A method for controlling a boost pressure of an internal combustion engine, comprising the steps of: determining an actual boost pressure of the internal combustion engine; determining a deviation between a reference boost pressure and the actual boost pressure; generating, as a function of the deviation, a manipulated variable for an actuator acting on an exhaust flow guided through a turbine of an exhaust-driven turbocharger; and transforming, in a characteristics map, at least a part of the manipulated variable into at least one value to provide an at least approximately linear correlation between the manipulated variable for the actuator acting on the exhaust flow guided through the turbine and the actual boost pressure of the internal combustion engine.