Report to stderr if status callback was called with invalid arguments
diff --git a/src/ideviceinstaller.c b/src/ideviceinstaller.c
index 0cf2b18..642d547 100644
--- a/src/ideviceinstaller.c
+++ b/src/ideviceinstaller.c
@@ -146,7 +146,7 @@
 			free(status_msg);
 		}
 	} else {
-		printf("%s: called with invalid data!\n", __func__);
+		fprintf(stderr, "ERROR: %s was called with invalid arguments!\n", __func__);
 	}
 }