diff --git a/src/byte_transmitter.v b/src/byte_transmitter.v
index 159be8a..2393862 100644
--- a/src/byte_transmitter.v
+++ b/src/byte_transmitter.v
@@ -38,6 +38,7 @@ module byte_transmitter (
 `ifdef FORMAL
           f_total_written <= f_total_written + 1;
           assert (r_out != 1'bX);
+          assert (in[byte_count-1] != 1'bX);
 `endif
           r_out <= in[byte_count-1];
           byte_count <= byte_count - 1;
diff --git a/src/project.v b/src/project.v
index 813477b..2f63878 100644
--- a/src/project.v
+++ b/src/project.v
@@ -28,16 +28,15 @@ module tt_um_jtag_example_stevej (
 
   wire tdo;
   wire interrupting;
-  assign uo_out = {
-    interrupting,
-    interrupting,
-    interrupting,
-    interrupting,
-    interrupting,
-    interrupting,
-    interrupting,
-    tdo
-  };
+  assign uo_out[7] = interrupting;
+  assign uo_out[6] = interrupting;
+  assign uo_out[5] = interrupting;
+  assign uo_out[4] = interrupting;
+  assign uo_out[3] = interrupting;
+  assign uo_out[2] = interrupting;
+  assign uo_out[1] = interrupting;
+  assign uo_out[0] = tdo;
+
   wire reset;
   assign reset = ~rst_n;