diff --git a/techlibs/xilinx/synth_xilinx.cc b/techlibs/xilinx/synth_xilinx.cc
index ee67beba7..fbcc96014 100644
--- a/techlibs/xilinx/synth_xilinx.cc
+++ b/techlibs/xilinx/synth_xilinx.cc
@@ -204,7 +204,7 @@ struct SynthXilinxPass : public Pass {
 
 		if (check_label(active, run_from, run_to, "map_luts"))
 		{
-			Pass::call(design, "abc -lut 5:8" + string(retime ? " -dff" : ""));
+			Pass::call(design, "abc -lut 6:8" + string(retime ? " -dff" : ""));
 			Pass::call(design, "clean");
 		}