diff --git a/techlibs/ice40/cells_sim.v b/techlibs/ice40/cells_sim.v
index 9c63336d7..def878216 100644
--- a/techlibs/ice40/cells_sim.v
+++ b/techlibs/ice40/cells_sim.v
@@ -245,9 +245,9 @@ endmodule
 
 // Packed IceStorm Logic Cells
 
-module ICESTORM_CARRYCONST (output O);
+module ICESTORM_CARRYCONST (output COUT);
 	parameter [0:0] CARRYCONST = 0;
-	assign O = CARRYCONST;
+	assign COUT = CARRYCONST;
 endmodule
 
 module ICESTORM_LC (