diff --git a/hw/ip/otbn/rtl/otbn.sv b/hw/ip/otbn/rtl/otbn.sv
index f7fc77a..187b511 100644
--- a/hw/ip/otbn/rtl/otbn.sv
+++ b/hw/ip/otbn/rtl/otbn.sv
@@ -37,11 +37,11 @@
 
   // The OTBN_*_SIZE parameters are auto-generated by regtool and come from the
   // bus window sizes; they are given in bytes.
-  localparam ImemSizeByte = otbn_reg_pkg::OTBN_IMEM_SIZE;
-  localparam DmemSizeByte = otbn_reg_pkg::OTBN_DMEM_SIZE;
+  localparam int ImemSizeByte = otbn_reg_pkg::OTBN_IMEM_SIZE;
+  localparam int DmemSizeByte = otbn_reg_pkg::OTBN_DMEM_SIZE;
 
-  localparam ImemAddrWidth = vbits(ImemSizeByte);
-  localparam DmemAddrWidth = vbits(DmemSizeByte);
+  localparam int ImemAddrWidth = vbits(ImemSizeByte);
+  localparam int DmemAddrWidth = vbits(DmemSizeByte);
 
   logic start;
   logic busy_d, busy_q;
@@ -154,8 +154,8 @@
 
   // Instruction Memory (IMEM) =================================================
 
-  localparam ImemSizeWords = ImemSizeByte / 4;
-  localparam ImemIndexWidth = vbits(ImemSizeWords);
+  localparam int ImemSizeWords = ImemSizeByte / 4;
+  localparam int ImemIndexWidth = vbits(ImemSizeWords);
 
   // Access select to IMEM: core (1), or bus (0)
   logic imem_access_core;
@@ -275,8 +275,8 @@
 
   // Data Memory (DMEM) ========================================================
 
-  localparam DmemSizeWords = DmemSizeByte / (WLEN / 8);
-  localparam DmemIndexWidth = vbits(DmemSizeWords);
+  localparam int DmemSizeWords = DmemSizeByte / (WLEN / 8);
+  localparam int DmemIndexWidth = vbits(DmemSizeWords);
 
   // Access select to DMEM: core (1), or bus (0)
   logic dmem_access_core;