diff --git a/compatibility_matrices/compatibility_matrix.4.xml b/compatibility_matrices/compatibility_matrix.4.xml
index 7d6fc609f8..21a0847cfc 100644
--- a/compatibility_matrices/compatibility_matrix.4.xml
+++ b/compatibility_matrices/compatibility_matrix.4.xml
@@ -354,6 +354,10 @@
             <instance>slot2</instance>
             <instance>slot3</instance>
         </interface>
+    </hal>
+    <hal format="hidl" optional="true">
+        <name>android.hardware.radio</name>
+        <version>1.2</version>
         <interface>
             <name>ISap</name>
             <instance>slot1</instance>