diff --git a/libs/binder/IActivityManager.cpp b/libs/binder/IActivityManager.cpp
index 87b295a..50a8b28 100644
--- a/libs/binder/IActivityManager.cpp
+++ b/libs/binder/IActivityManager.cpp
@@ -36,6 +36,7 @@
     virtual int openContentUri(const String16& stringUri)
     {
         Parcel data, reply;
+        data.writeInterfaceToken(IActivityManager::getInterfaceDescriptor());
         data.writeString16(stringUri);
         status_t ret = remote()->transact(OPEN_CONTENT_URI_TRANSACTION, data, & reply);
         int fd = -1;