diff --git a/hw/efinix_fpga/simulation/tbs/mapper_tb.sv b/hw/efinix_fpga/simulation/tbs/mapper_tb.sv
index ab62128..0f82882 100644
--- a/hw/efinix_fpga/simulation/tbs/mapper_tb.sv
+++ b/hw/efinix_fpga/simulation/tbs/mapper_tb.sv
@@ -61,7 +61,14 @@ endtask
 
 int errors;
 
+int rnd_values [16];
+
 initial begin
+    for (int i = 0; i < 16; i++) begin
+        rnd_values[i] = $urandom();
+    end
+
+
     errors = 0;
     repeat (5) @(posedge r_clk_cpu);
     reset = 1;
@@ -73,14 +80,19 @@ initial begin
     reset = 0;
     repeat (5) @(posedge r_clk_cpu);
 
-    write_reg(0, 8'haa);
-    write_reg(1, 8'hbb);
+
+    for (int i = 0; i < 16; i++) begin
+        write_reg(2*i,     rnd_values[i][7:0]);
+        write_reg(2*i + 1, rnd_values[i][15:8]);
+    end
 
     repeat (5) @(posedge r_clk_cpu);
 
-    assert (u_mapper.mm[0] == 16'hbbaa) else begin
-        $error("mm[0] expected 0xbbaa got 0x%x", u_mapper.mm[0]);
-        errors += 1;
+    for (int i = 0; i < 16; i++) begin
+        assert (u_mapper.mm[i] == rnd_values[i][15:0]) else begin
+            $error("mm[%d] expected 0x%x got 0x%x", i, rnd_values[i][15:0], u_mapper.mm[i]);
+            errors += 1;
+        end
     end
 
     if (errors != 0) begin
diff --git a/hw/efinix_fpga/src/mapper.sv b/hw/efinix_fpga/src/mapper.sv
index 48ac8d3..83f7a07 100644
--- a/hw/efinix_fpga/src/mapper.sv
+++ b/hw/efinix_fpga/src/mapper.sv
@@ -28,7 +28,7 @@ always_ff @(negedge i_clk or posedge i_reset) begin
         end
     end
 
-    for (int i = 0; i < 31; i++) begin
+    for (int i = 0; i < 32; i++) begin
         if (we[i]) begin
             mm[i/2][(i%2)*8 +: 8] <= i_data;
         end