In People v. Dubose (1971) 17 Cal.App.3d 43, the court expressly refused to extend the statutory exception of subdivision (h) to allow a second pretrial motion based on newly discovered evidence. In Dubose, the defendant predicated a second section 1538.5 motion on evidence derived from a habeas corpus hearing held subsequent to his first motion. The court emphasized that the subdivision (h) exception for lack of opportunity or unknown grounds applies "only where the motion is made for the first time at trial." ( Id., at p. 47.)