“Does anyone know why there is no published OH on some parts of Shulchan Oruch? In his introduction he writes that he is publishing on all 4 chalokim, yet some parts (eg Yayin Nesech and Hilchos Avodo Zoro) are unfortunately not available. Did he never write them or are they lost?”
They recently printed Hilchos Nedarim from manuscripts. So it’s possible that there are more manuscripts that may yet see the light of day.