diff --git a/contrib/es9p_client.py b/contrib/es9p_client.py
index e9a71fc0..c1455dc7 100755
--- a/contrib/es9p_client.py
+++ b/contrib/es9p_client.py
@@ -128,12 +128,12 @@ class Es9pClient:
 
         if self.opts.operation == 'download':
             pird = {
-                'transactionId': self.opts.transaction_id,
+                'transactionId': h2b(self.opts.transaction_id),
                 'notificationMetadata': ntf_metadata,
                 'smdpOid': self.opts.smdpp_oid,
                 'finalResult': ('successResult', {
-                    'aid': self.opts.isdp_aid,
-                    'simaResponse': self.opts.sima_response,
+                    'aid': h2b(self.opts.isdp_aid),
+                    'simaResponse': h2b(self.opts.sima_response),
                     }),
             }
             pird_bin = rsp.asn1.encode('ProfileInstallationResultData', pird)