The phase flicker in digital liquid crystal on silicon (LCOS) device introduces temporal phase noise to the phase pattern displayed on the device. Such temporal phase noise could elevate the power of unwanted diffraction orders and ultimately cause crosstalk in optical switches based on the LCOS technology. Building on our previous work, this paper demonstrated an automated phase flicker optimisation process by using the genetic algorithm. The method developed in this work further shortened the optimisation process by 10x. It was also demonstrated that the optimised digital driving waveform set was able to reduce the crosstalk level in the optical switches by at least 3 dB.