diff --git a/scripts/phase0/function_puller.py b/scripts/phase0/function_puller.py
index 393f821d5..830e52a32 100644
--- a/scripts/phase0/function_puller.py
+++ b/scripts/phase0/function_puller.py
@@ -39,7 +39,7 @@ def get_spec(file_name: str, phase:int = 0) -> List[str]:
         else:
             if pulling_from == linenum and line == '{':
                 if is_update_section:
-                    code_lines.append('%s = SSZTypeExtension({' % current_name)
+                    code_lines.append('%s = SSZTypeExtension(%s, {' % (current_name, current_name))
                 else:
                     code_lines.append('%s = SSZType({' % current_name)
                 current_typedef = ['global_vars["%s"] = SSZType({' % current_name]
diff --git a/specs/core/1_custody-game.md b/specs/core/1_custody-game.md
index c510abf6c..5de52a4ea 100644
--- a/specs/core/1_custody-game.md
+++ b/specs/core/1_custody-game.md
@@ -134,7 +134,7 @@ This document details the beacon chain additions and changes in Phase 1 of Ether
     'attestation': Attestation,
     'challenger_index': ValidatorIndex,
     'responder_key': BLSSignature,
-    'chunk_bits': Bitfield,
+    'chunk_bits': "bytes",
     'signature': BLSSignature,
 }
 ```
@@ -147,7 +147,7 @@ This document details the beacon chain additions and changes in Phase 1 of Ether
     'challenger_index': ValidatorIndex,
     'responder_index': ValidatorIndex,
     'deadline': Epoch,
-    'crosslink_data_root': Hash,
+    'crosslink_data_root': 'bytes32',
     'depth': 'uint64',
     'chunk_index': 'uint64',
 }
@@ -161,9 +161,9 @@ This document details the beacon chain additions and changes in Phase 1 of Ether
     'challenger_index': ValidatorIndex,
     'responder_index': ValidatorIndex,
     'deadline': Epoch,
-    'crosslink_data_root': Hash,
+    'crosslink_data_root': 'bytes32',
     'chunk_count': 'uint64',
-    'chunk_bits_merkle_root': Hash,
+    'chunk_bits_merkle_root': 'bytes32',
     'responder_key': BLSSignature,
 }
 ```
@@ -175,9 +175,9 @@ This document details the beacon chain additions and changes in Phase 1 of Ether
     'challenge_index': 'uint64',
     'chunk_index': 'uint64',
     'chunk': ['byte', BYTES_PER_CUSTODY_CHUNK],
-    'data_branch': [Hash],
-    'chunk_bits_branch': [Hash],
-    'chunk_bits_leaf': Hash,
+    'data_branch': ['bytes32'],
+    'chunk_bits_branch': ['bytes32'],
+    'chunk_bits_leaf': 'bytes32',
 }
 ```
 
@@ -287,7 +287,7 @@ def get_custody_chunk_bit(key: BLSSignature, chunk: bytes) -> bool:
 ### `get_chunk_bits_root`
 
 ```python
-def get_chunk_bits_root(chunk_bitfield: Bitfield) -> Bytes32:
+def get_chunk_bits_root(chunk_bitfield: bytes) -> Bytes32:
     aggregated_bits = bytearray([0] * 32)
     for i in range(0, len(chunk_bitfield), 32):
         for j in range(32):
diff --git a/specs/core/1_shard-data-chains.md b/specs/core/1_shard-data-chains.md
index c277dbdc3..691e38c04 100644
--- a/specs/core/1_shard-data-chains.md
+++ b/specs/core/1_shard-data-chains.md
@@ -15,9 +15,9 @@
         - [Signature domains](#signature-domains)
     - [Data structures](#data-structures)
         - [`ShardBlockBody`](#shardblockbody)
+        - [`ShardAttestation`](#shardattestation)
         - [`ShardBlock`](#shardblock)
         - [`ShardBlockHeader`](#shardblockheader)
-        - [`ShardAttestation`](#shardattestation)
     - [Helper functions](#helper-functions)
         - [`get_period_committee`](#get_period_committee)
         - [`get_switchover_epoch`](#get_switchover_epoch)
@@ -68,7 +68,23 @@ This document describes the shard data layer and the shard fork choice rule in P
 ### `ShardBlockBody`
 
 ```python
-['byte', BYTES_PER_SHARD_BLOCK_BODY]
+{
+    'data': ['byte', BYTES_PER_SHARD_BLOCK_BODY],
+}
+```
+
+### `ShardAttestation`
+
+```python
+{
+    'data': {
+        'slot': Slot,
+        'shard': Shard,
+        'shard_block_root': 'bytes32',
+    },
+    'aggregation_bitfield': 'bytes',
+    'aggregate_signature': BLSSignature,
+}
 ```
 
 ### `ShardBlock`
@@ -77,10 +93,10 @@ This document describes the shard data layer and the shard fork choice rule in P
 {
     'slot': Slot,
     'shard': Shard,
-    'beacon_chain_root': Hash,
-    'previous_block_root': Hash,
+    'beacon_chain_root': 'bytes32',
+    'previous_block_root': 'bytes32',
     'data': ShardBlockBody,
-    'state_root': Hash,
+    'state_root': 'bytes32',
     'attestations': [ShardAttestation],
     'signature': BLSSignature,
 }
@@ -92,29 +108,15 @@ This document describes the shard data layer and the shard fork choice rule in P
 {
     'slot': Slot,
     'shard': Shard,
-    'beacon_chain_root': Hash,
-    'previous_block_root': Hash,
-    'body_root': Hash,
-    'state_root': Hash,
+    'beacon_chain_root': 'bytes32',
+    'previous_block_root': 'bytes32',
+    'body_root': 'bytes32',
+    'state_root': 'bytes32',
     'attestations': [ShardAttestation],
     'signature': BLSSignature,
 }
 ```
 
-### `ShardAttestation`
-
-```python
-{
-    'data': {
-        'slot': Slot,
-        'shard': Shard,
-        'shard_block_root': Hash,
-    },
-    'aggregation_bitfield': Bitfield,
-    'aggregate_signature': BLSSignature,
-}
-```
-
 ## Helper functions
 
 ### `get_period_committee`
@@ -234,7 +236,7 @@ def verify_shard_attestation_signature(state: BeaconState,
 ### `compute_crosslink_data_root`
 
 ```python
-def compute_crosslink_data_root(blocks: List[ShardBlock]) -> Hash:
+def compute_crosslink_data_root(blocks: List[ShardBlock]) -> 'bytes32':
     def is_power_of_two(value: int) -> bool:
         return (value > 0) and (value & (value - 1) == 0)
 
@@ -272,7 +274,7 @@ Let:
 def is_valid_shard_block(beacon_blocks: List[BeaconBlock],
                          beacon_state: BeaconState,
                          valid_shard_blocks: List[ShardBlock],
-                         unix_time: uint64,
+                         unix_time: int,
                          candidate: ShardBlock) -> bool:
     # Check if block is already determined valid
     for _, block in enumerate(valid_shard_blocks):