Multi-beam pattern generators employing yaw correction when writing upon large substrates, and associated methods are disclosed. A multi-beam pattern generator may include a spatial light modulator (SLM) with independently controllable mirrors to reflect light onto a substrate to write a pattern. The pattern may be written in writing cycles where the substrate is moved to writing cycle zone locations. The light is reflected by the SLM onto the substrate by mirrors of the SLM in active positions to write the pattern upon the substrate. By determining a location and yaw of the substrate with respect to the SLM in each writing cycle, some mirrors of the SLM may be digitally controlled to either inactive positions or the active positions to compensate for the yaw of the substrate. In this manner, the pattern written upon the substrate may be precisely written with compensation for yaw.