diff --git a/verilog/rtl/sysctrl.v b/verilog/rtl/sysctrl.v
index 93f2dcb..8a694aa 100644
--- a/verilog/rtl/sysctrl.v
+++ b/verilog/rtl/sysctrl.v
@@ -11,6 +11,7 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+// SPDX-License-Identifier: Apache-2.0
 
 `default_nettype none
 module sysctrl_wb #(