diff --git a/techlibs/greenpak4/synth_greenpak4.cc b/techlibs/greenpak4/synth_greenpak4.cc
index 10db06cd..ec1b687b 100644
--- a/techlibs/greenpak4/synth_greenpak4.cc
+++ b/techlibs/greenpak4/synth_greenpak4.cc
@@ -175,6 +175,7 @@ struct SynthGreenPAK4Pass : public ScriptPass
 
 		if (check_label("map_cells"))
 		{
+			run("shregmap -tech greenpak4");
 			run("dfflibmap -liberty +/greenpak4/gp_dff.lib");
 			run("techmap -map +/greenpak4/cells_map.v");
 			run("dffinit -ff GP_DFF Q INIT");