diff --git a/tools/idf_tools.py b/tools/idf_tools.py
index 9e6c6c8537..eba2a53e76 100755
--- a/tools/idf_tools.py
+++ b/tools/idf_tools.py
@@ -143,7 +143,7 @@ CURRENT_PLATFORM = PLATFORM_FROM_NAME.get(PYTHON_PLATFORM, UNKNOWN_PLATFORM)
 EXPORT_SHELL = 'shell'
 EXPORT_KEY_VALUE = 'key-value'
 
-ISRG_X1_ROOT_CERT = """
+ISRG_X1_ROOT_CERT = u"""
 -----BEGIN CERTIFICATE-----
 MIIFazCCA1OgAwIBAgIRAIIQz7DSQONZRGPgu2OCiwAwDQYJKoZIhvcNAQELBQAw
 TzELMAkGA1UEBhMCVVMxKTAnBgNVBAoTIEludGVybmV0IFNlY3VyaXR5IFJlc2Vh