diff --git a/python/graminelibos/manifest.py b/python/graminelibos/manifest.py
index 7918593bf2..8a57ef9267 100644
--- a/python/graminelibos/manifest.py
+++ b/python/graminelibos/manifest.py
@@ -96,8 +96,8 @@ def __init__(self, manifest_str):
         sgx.setdefault('isvprodid', 0)
         sgx.setdefault('isvsvn', 0)
         sgx.setdefault('kss', False)
-        sgx.setdefault('isvextprodid', b'\x00'*16)
-        sgx.setdefault('isvfamilyid', b'\x00'*16)
+        sgx.setdefault('isvextprodid', 0)
+        sgx.setdefault('isvfamilyid', 0)
         sgx.setdefault('remote_attestation', "none")
         sgx.setdefault('debug', False)
         sgx.setdefault('require_avx', False)