diff --git a/src/core/osmo_io.c b/src/core/osmo_io.c
index d52d601..57eba6c 100644
--- a/src/core/osmo_io.c
+++ b/src/core/osmo_io.c
@@ -106,6 +106,8 @@
 	}
 
 	OSMO_ASSERT(osmo_iofd_ops.close);
+	OSMO_ASSERT(osmo_iofd_ops.register_fd);
+	OSMO_ASSERT(osmo_iofd_ops.unregister_fd);
 	OSMO_ASSERT(osmo_iofd_ops.write_enable);
 	OSMO_ASSERT(osmo_iofd_ops.write_disable);
 	OSMO_ASSERT(osmo_iofd_ops.read_enable);
@@ -695,8 +697,7 @@
 		return -EBADF;
 	}
 
-	if (osmo_iofd_ops.register_fd)
-		rc = osmo_iofd_ops.register_fd(iofd);
+	rc = osmo_iofd_ops.register_fd(iofd);
 	if (rc)
 		return rc;
 
@@ -720,11 +721,7 @@
  */
 int osmo_iofd_unregister(struct osmo_io_fd *iofd)
 {
-	if (osmo_iofd_ops.unregister_fd)
-		return osmo_iofd_ops.unregister_fd(iofd);
-	IOFD_FLAG_SET(iofd, IOFD_FLAG_CLOSED);
-
-	return 0;
+	return osmo_iofd_ops.unregister_fd(iofd);
 }
 
 /*! Get the number of messages in the tx queue.