diff --git a/Makefile b/Makefile
index 0826893..53aeb42 100644
--- a/Makefile
+++ b/Makefile
@@ -15,7 +15,6 @@ prog: pixelflut.bit
 	openFPGALoader -b arty_a7_35t $<
 
 sim: dvi_tb.vcd
-	gtkwave $<
 
 pixelflut.bit: pixelflut.frames
 	xc7frames2bit --part_file "$(XRAY_DATABASE_DIR)/artix7/$(PART)/part.yaml" --part_name $(PART) --frm_file $< --output_file $@