A method for producing a single-layer diffractive combiner for a head-up display having a projection unit with n light sources of \u03bbi wavelength, where i=1 to n sending light towards the combiner at an angle \u03b8p. A boot of a second operating system kernel is then initiated while preserving in the tagged region of the volatile memory contents stored therein. A first heater is configured to heat the cold head to keep a temperature of the transition edge sensor constant. The first multiplexer receives a control signal that selects between the macro output and the inverted version of such output to produce a first multiplexer output.