diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py
index 2126d11..92a46a2 100755
--- a/tools/releasetools/ota_from_target_files.py
+++ b/tools/releasetools/ota_from_target_files.py
@@ -318,7 +318,7 @@
     common.RunAndCheckOutput(cmd)
     with open(out_signature_size_file) as f:
       signature_size = f.read().rstrip()
-    logger.info("% outputs the maximum signature size: %", cmd[0],
+    logger.info("%s outputs the maximum signature size: %s", cmd[0],
                 signature_size)
     return int(signature_size)