diff --git a/examples/gowin/demo.v b/examples/gowin/demo.v
index f5c001893..485fec97f 100644
--- a/examples/gowin/demo.v
+++ b/examples/gowin/demo.v
@@ -1,7 +1,7 @@
 module demo (
 	input clk,
-	output [15:0] leds
-	//,output unused
+	output [15:0] leds,
+	output unused
 );
 	localparam PRESCALE = 20;
 	reg [PRESCALE+3:0] counter = 0;
diff --git a/techlibs/gowin/synth_gowin.cc b/techlibs/gowin/synth_gowin.cc
index 0bfa9da1a..f7a5006bc 100644
--- a/techlibs/gowin/synth_gowin.cc
+++ b/techlibs/gowin/synth_gowin.cc
@@ -210,6 +210,7 @@ struct SynthGowinPass : public ScriptPass
 		if (check_label("map_cells"))
 		{
 			run("techmap -map +/gowin/cells_map.v");
+			run("setundef -undriven -zero");
 			run("hilomap -hicell VCC V -locell GND G");
 			run("iopadmap -bits -inpad IBUF O:I -outpad OBUF I:O", "(unless -noiopads)");
 			run("dffinit  -ff DFF Q INIT");