diff --git a/setup.py b/setup.py
index 911eb65b0e..d1c62fb72f 100644
--- a/setup.py
+++ b/setup.py
@@ -499,7 +499,7 @@ def run(self):
         "pycryptodome==3.9.4",
         "py_ecc==2.0.0",
         "dataclasses==0.6",
-        "remerkleable==0.1.12",
+        "remerkleable==0.1.13",
         "ruamel.yaml==0.16.5",
         "lru-dict==1.1.6"
     ]
diff --git a/tests/core/pyspec/eth2spec/config/config_util.py b/tests/core/pyspec/eth2spec/config/config_util.py
index 64c533f2d1..4c5768a294 100644
--- a/tests/core/pyspec/eth2spec/config/config_util.py
+++ b/tests/core/pyspec/eth2spec/config/config_util.py
@@ -8,13 +8,18 @@
 
 # Access to overwrite spec constants based on configuration
 # This is called by the spec module after declaring its globals, and applies the loaded presets.
-def apply_constants_config(spec_globals: Dict[str, Any]) -> None:
+def apply_constants_config(spec_globals: Dict[str, Any], warn_if_unknown: bool = False) -> None:
     global config
     for k, v in config.items():
-        if k.startswith('DOMAIN_'):
-            spec_globals[k] = spec_globals['DomainType'](v)  # domain types are defined as bytes in the configs
+        # the spec should have default values for everything, if not, the config key is invalid.
+        if k in spec_globals:
+            # Keep the same type as the default value indicates (which may be an SSZ basic type subclass, e.g. 'Gwei')
+            spec_globals[k] = spec_globals[k].__class__(v)
         else:
-            spec_globals[k] = v
+            # Note: Phase 0 spec will not know the phase 1 config values.
+            # Yet, during debugging you can enable explicit warnings.
+            if warn_if_unknown:
+                print(f"WARNING: unknown config key: '{k}' with value: '{v}'")
 
 
 # Load presets from a file, and then prepares the global config setting. This does not apply the config.
diff --git a/tests/core/pyspec/eth2spec/test/phase_0/epoch_processing/test_process_justification_and_finalization.py b/tests/core/pyspec/eth2spec/test/phase_0/epoch_processing/test_process_justification_and_finalization.py
index 9f9e1c316b..09af2126db 100644
--- a/tests/core/pyspec/eth2spec/test/phase_0/epoch_processing/test_process_justification_and_finalization.py
+++ b/tests/core/pyspec/eth2spec/test/phase_0/epoch_processing/test_process_justification_and_finalization.py
@@ -24,7 +24,7 @@ def add_mock_attestations(spec, state, epoch, source, target, sufficient_support
         raise Exception(f"cannot include attestations in epoch ${epoch} from epoch ${current_epoch}")
 
     total_balance = spec.get_total_active_balance(state)
-    remaining_balance = total_balance * 2 // 3
+    remaining_balance = int(total_balance * 2 // 3)  # can become negative
 
     start_slot = spec.compute_start_slot_at_epoch(epoch)
     for slot in range(start_slot, start_slot + spec.SLOTS_PER_EPOCH):
@@ -42,7 +42,7 @@ def add_mock_attestations(spec, state, epoch, source, target, sufficient_support
             aggregation_bits = [0] * len(committee)
             for v in range(len(committee) * 2 // 3 + 1):
                 if remaining_balance > 0:
-                    remaining_balance -= state.validators[v].effective_balance
+                    remaining_balance -= int(state.validators[v].effective_balance)
                     aggregation_bits[v] = 1
                 else:
                     break