diff --git a/geometry.cpp b/geometry.cpp
index f3f85609..715deae4 100644
--- a/geometry.cpp
+++ b/geometry.cpp
@@ -914,6 +914,8 @@ EX void check_cgi() {
   
   if(binarytiling || GDIM == 3) V("WQ", its(vid.texture_step));
   
+  if(hybri) V("U", its(int(hybrid::underlying)));
+  
   if(prod) V("PL", fts(vid.plevel_factor));
   
   if(binarytiling) V("BT", fts(vid.binary_width));