diff --git a/examples/simple_system/rtl/ibex_simple_system.sv b/examples/simple_system/rtl/ibex_simple_system.sv
index 7e8f7c16..06291ab7 100644
--- a/examples/simple_system/rtl/ibex_simple_system.sv
+++ b/examples/simple_system/rtl/ibex_simple_system.sv
@@ -46,8 +46,8 @@ module ibex_simple_system (
     Timer
   } bus_device_e;
 
-  localparam NrDevices = 3;
-  localparam NrHosts = 1;
+  localparam int NrDevices = 3;
+  localparam int NrHosts = 1;
 
   // interrupts
   logic timer_irq;