diff --git a/tests/core/pyspec/eth2spec/gen_helpers/gen_base/gen_runner.py b/tests/core/pyspec/eth2spec/gen_helpers/gen_base/gen_runner.py
index 1d2b03fd2..dccb9313f 100644
--- a/tests/core/pyspec/eth2spec/gen_helpers/gen_base/gen_runner.py
+++ b/tests/core/pyspec/eth2spec/gen_helpers/gen_base/gen_runner.py
@@ -9,7 +9,6 @@ import sys
 import json
 from typing import Iterable, AnyStr, Any, Callable
 import traceback
-
 from ruamel.yaml import (
     YAML,
 )
@@ -98,6 +97,11 @@ def run_generator(generator_name, test_providers: Iterable[TestProvider]):
     yaml = YAML(pure=True)
     yaml.default_flow_style = None
 
+    def _represent_none(self, _):
+        return self.represent_scalar('tag:yaml.org,2002:null', 'null')
+
+    yaml.representer.add_representer(type(None), _represent_none)
+
     # Spec config is using a YAML subset
     cfg_yaml = YAML(pure=True)
     cfg_yaml.default_flow_style = False  # Emit separate line for each key
diff --git a/tests/core/pyspec/eth2spec/test/helpers/optimistic_sync.py b/tests/core/pyspec/eth2spec/test/helpers/optimistic_sync.py
index d88513a8a..a89c3083e 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/optimistic_sync.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/optimistic_sync.py
@@ -42,9 +42,9 @@ class PayloadStatusV1:
     @property
     def formatted_output(self):
         return {
-            'status': str(self.status),
-            'latest_valid_hash': encode_hex(self.latest_valid_hash) if self.latest_valid_hash is not None else 'null',
-            'validation_error': str(self.validation_error) if self.validation_error is not None else 'null'
+            'status': str(self.status.value),
+            'latest_valid_hash': encode_hex(self.latest_valid_hash) if self.latest_valid_hash is not None else None,
+            'validation_error': str(self.validation_error) if self.validation_error is not None else None
         }
 
 
@@ -95,6 +95,7 @@ def add_optimistic_block(spec, mega_store, signed_block, test_steps,
 
     mega_store.block_payload_statuses[block_root] = payload_status
     test_steps.append({
+        'block_hash': encode_hex(el_block_hash),
         'payload_status': payload_status.formatted_output,
     })