diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/driver/CordioHCIDriver.h b/features/FEATURE_BLE/targets/TARGET_CORDIO/driver/CordioHCIDriver.h
index 10ac769c82..a3b923e270 100644
--- a/features/FEATURE_BLE/targets/TARGET_CORDIO/driver/CordioHCIDriver.h
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/driver/CordioHCIDriver.h
@@ -58,6 +58,10 @@ struct buf_pool_desc_t {
  *   - Access to the write function of the underlying HCITransport driver.
  */
 class CordioHCIDriver {
+
+    // hook for internal tests and passthrough driver
+    friend class CordioHCIHook;
+
 public:
     /**
      * Construct a new instance of an HCI driver.
diff --git a/features/FEATURE_BLE/targets/TARGET_CORDIO/driver/CordioHCITransportDriver.h b/features/FEATURE_BLE/targets/TARGET_CORDIO/driver/CordioHCITransportDriver.h
index a7e7499f21..b33d407909 100644
--- a/features/FEATURE_BLE/targets/TARGET_CORDIO/driver/CordioHCITransportDriver.h
+++ b/features/FEATURE_BLE/targets/TARGET_CORDIO/driver/CordioHCITransportDriver.h
@@ -28,6 +28,10 @@ namespace cordio {
  * It allow the stack to write data in the HCI channel.
  */
 class CordioHCITransportDriver {
+
+    // hook for internal tests and passthrough driver
+    friend class CordioHCIHook;
+
 public:
     /**
      * Driver destructor.