diff --git a/examples/simple_system/rtl/ibex_simple_system.sv b/examples/simple_system/rtl/ibex_simple_system.sv
index e2b9af12..d9647335 100644
--- a/examples/simple_system/rtl/ibex_simple_system.sv
+++ b/examples/simple_system/rtl/ibex_simple_system.sv
@@ -210,7 +210,7 @@ module ibex_simple_system (
       .clk_i                  (clk_sys),
       .rst_ni                 (rst_sys_n),
 
-      .test_en_i              ('b0),
+      .test_en_i              (1'b0),
       .scan_rst_ni            (1'b1),
       .ram_cfg_i              (prim_ram_1p_pkg::RAM_1P_CFG_DEFAULT),
 
@@ -249,7 +249,7 @@ module ibex_simple_system (
       .scramble_nonce_i       ('0),
       .scramble_req_o         (),
 
-      .debug_req_i            ('b0),
+      .debug_req_i            (1'b0),
       .crash_dump_o           (),
       .double_fault_seen_o    (),