diff --git a/passes/techmap/abc9.cc b/passes/techmap/abc9.cc
index 147d6e572..60a88f729 100644
--- a/passes/techmap/abc9.cc
+++ b/passes/techmap/abc9.cc
@@ -330,7 +330,10 @@ struct Abc9Pass : public ScriptPass
 			run("design -stash $abc9_map");
 			run("design -load $abc9");
 			run("design -delete $abc9");
-			run("techmap -wb -max_iter 1 -map %$abc9_map -map +/abc9_map.v");
+			if (help_mode)
+				run("techmap -wb -max_iter 1 -map %$abc9_map -map +/abc9_map.v [-D DFF]", "(option if -dff)");
+			else
+				run(stringf("techmap -wb -max_iter 1 -map %$abc9_map -map +/abc9_map.v %s", dff_mode ? "-D DFF" : ""));
 			run("design -delete $abc9_map");
 		}
 
diff --git a/techlibs/common/abc9_map.v b/techlibs/common/abc9_map.v
index 5f1822485..57b3831d8 100644
--- a/techlibs/common/abc9_map.v
+++ b/techlibs/common/abc9_map.v
@@ -1,3 +1,4 @@
+`ifdef DFF
 (* techmap_celltype = "$_DFF_N_ $_DFF_P_" *)
 module $_DFF_x_(input C, D, output Q);
   parameter [0:0] _TECHMAP_WIREINIT_Q_ = 1'bx;
@@ -23,3 +24,4 @@ module $_DFF_x_(input C, D, output Q);
     $error("Unrecognised _TECHMAP_CELLTYPE_");
   endgenerate
 endmodule
+`endif