Ethanolamine phosphate transferase involved in glycosylphosphatidylinositol-anchor biosynthesis. Transfers ethanolamine phosphate to the GPI second mannose (By similarity). Glycolipid biosynthesis; glycosylphosphatidylinositol-anchor biosynthesis. Cell-wall protein anchorage defects. Belongs to the PIGG/PIGN/PIGO family. PIGG subfamily.