diff --git a/techlibs/nanoxplore/arith_map.v b/techlibs/nanoxplore/arith_map.v
index 39d03229dce..26bd67bfb88 100644
--- a/techlibs/nanoxplore/arith_map.v
+++ b/techlibs/nanoxplore/arith_map.v
@@ -66,8 +66,8 @@ module _80_nx_cy_alu (A, B, CI, BI, X, Y, CO);
 
 	NX_CY_1BIT alu_cout(
 		.CI(COx[Y_WIDTH-1]),
-		.A(1'b0),
-		.B(1'b0),
+		.A(1'b1),
+		.B(1'b1),
 		.S(CO[Y_WIDTH-1])
 	);