diff --git a/scripts/function_puller.py b/scripts/function_puller.py
index 26671bafc..b30e5b75c 100644
--- a/scripts/function_puller.py
+++ b/scripts/function_puller.py
@@ -81,7 +81,7 @@ def get_spec(file_name: str) -> SpecObject:
                         if c not in 'ABCDEFGHIJKLMNOPQRSTUVWXYZ_0123456789':
                             is_constant_def = False
                     if is_constant_def:
-                        constants[row[0]] = row[1].replace('**TBD**', '0x1234567890123456789012345678901234567890')
+                        constants[row[0]] = row[1].replace('**TBD**', '2**32')
                     elif row[1].startswith('uint') or row[1].startswith('Bytes'):
                         custom_types[row[0]] = row[1]
     return functions, custom_types, constants, ssz_objects, inserts
diff --git a/specs/core/1_shard-data-chains.md b/specs/core/1_shard-data-chains.md
index 9293a50da..69962b6fe 100644
--- a/specs/core/1_shard-data-chains.md
+++ b/specs/core/1_shard-data-chains.md
@@ -247,6 +247,11 @@ def get_genesis_shard_state(shard: Shard) -> ShardState:
     return ShardState(
         shard=shard,
         slot=ShardSlot(SHARD_GENESIS_EPOCH * SHARD_SLOTS_PER_EPOCH),
+        latest_block_header=ShardBlockHeader(
+            shard=shard,
+            slot=ShardSlot(SHARD_GENESIS_EPOCH * SHARD_SLOTS_PER_EPOCH),
+            body_root=hash_tree_root(List[byte, MAX_SHARD_BLOCK_SIZE - SHARD_HEADER_SIZE]()),
+        ),
         block_body_price=MIN_BLOCK_BODY_PRICE,
     )
 ```
@@ -333,10 +338,19 @@ def process_shard_block_header(beacon_state: BeaconState, shard_state: ShardStat
     # Verify the slot number
     assert block.slot == shard_state.slot
     # Verify the beacon chain root
-    parent_epoch = compute_epoch_of_shard_slot(shard_state.latest_block_header.slot)
-    assert block.beacon_block_root == get_block_root(beacon_state, parent_epoch)
+    epoch = compute_epoch_of_shard_slot(shard_state.slot)
+    assert epoch * SLOTS_PER_EPOCH == beacon_state.slot
+    beacon_block_header = BeaconBlockHeader(
+        slot=beacon_state.latest_block_header.slot,
+        parent_root=beacon_state.latest_block_header.parent_root,
+        state_root=beacon_state.latest_block_header.state_root,
+        body_root=beacon_state.latest_block_header.body_root,
+    )
+    if beacon_block_header.state_root == Bytes32():
+        beacon_block_header.state_root = hash_tree_root(beacon_state)
+    assert block.beacon_block_root == signing_root(beacon_block_header)
     # Verify the parent root
-    assert block.parent_root == hash_tree_root(shard_state.latest_block_header)
+    assert block.parent_root == signing_root(shard_state.latest_block_header)
     # Save current block as the new latest block
     shard_state.latest_block_header = ShardBlockHeader(
         shard=block.shard,
@@ -379,7 +393,7 @@ def process_shard_attestations(beacon_state: BeaconState, shard_state: ShardStat
         assert block.aggregation_bits[i] == 0b0
     # Verify attester aggregate signature
     domain = get_domain(beacon_state, DOMAIN_SHARD_ATTESTER, compute_epoch_of_shard_slot(block.slot))
-    message = hash_tree_root(ShardAttestationData(shard_state.slot, block.parent_root))
+    message = hash_tree_root(ShardAttestationData(slot=shard_state.slot, parent_root=block.parent_root))
     assert bls_verify(bls_aggregate_pubkeys(pubkeys), message, block.attestations, domain)
     # Proposer micro-reward
     proposer_index = get_shard_proposer_index(beacon_state, shard_state.shard, block.slot)
diff --git a/test_libs/pyspec/eth2spec/test/helpers/phase1/attestations.py b/test_libs/pyspec/eth2spec/test/helpers/phase1/attestations.py
index 750ab5048..4f0a9fb0a 100644
--- a/test_libs/pyspec/eth2spec/test/helpers/phase1/attestations.py
+++ b/test_libs/pyspec/eth2spec/test/helpers/phase1/attestations.py
@@ -5,17 +5,20 @@ from eth2spec.utils.bls import (
 )
 
 
-def sign_shard_attestation(spec, shard_state, beacon_state, block, participants):
+def sign_shard_attestation(spec, beacon_state, shard_state, block, participants):
     signatures = []
-    message_hash = block.core.parent_root
-    block_epoch = spec.compute_epoch_of_shard_slot(block.core.slot)
+    message_hash = spec.ShardAttestationData(
+        slot=block.slot,
+        parent_root=block.parent_root,
+    ).hash_tree_root()
+    block_epoch = spec.compute_epoch_of_shard_slot(block.slot)
     for validator_index in participants:
         privkey = privkeys[validator_index]
         signatures.append(
             get_attestation_signature(
                 spec,
-                shard_state,
                 beacon_state,
+                shard_state,
                 message_hash,
                 block_epoch,
                 privkey,
@@ -25,7 +28,7 @@ def sign_shard_attestation(spec, shard_state, beacon_state, block, participants)
     return bls_aggregate_signatures(signatures)
 
 
-def get_attestation_signature(spec, shard_state, beacon_state, message_hash, block_epoch, privkey):
+def get_attestation_signature(spec, beacon_state, shard_state, message_hash, block_epoch, privkey):
     return bls_sign(
         message_hash=message_hash,
         privkey=privkey,
diff --git a/test_libs/pyspec/eth2spec/test/helpers/phase1/shard_block.py b/test_libs/pyspec/eth2spec/test/helpers/phase1/shard_block.py
index b9c388a3f..7955c613e 100644
--- a/test_libs/pyspec/eth2spec/test/helpers/phase1/shard_block.py
+++ b/test_libs/pyspec/eth2spec/test/helpers/phase1/shard_block.py
@@ -1,3 +1,5 @@
+from copy import deepcopy
+
 from eth2spec.test.helpers.keys import privkeys
 from eth2spec.utils.bls import (
     bls_sign,
@@ -13,69 +15,68 @@ from .attestations import (
 
 
 @only_with_bls()
-def sign_shard_block(spec, state, block, shard, proposer_index=None):
+def sign_shard_block(spec, beacon_state, shard_state, block, proposer_index=None):
     if proposer_index is None:
-        proposer_index = spec.get_shard_block_proposer_index(state, shard, block.core.slot)
+        proposer_index = spec.get_shard_proposer_index(beacon_state, shard_state.shard, block.slot)
 
     privkey = privkeys[proposer_index]
 
-    block.signatures.proposer_signature = bls_sign(
+    block.signature = bls_sign(
         message_hash=signing_root(block),
         privkey=privkey,
         domain=spec.get_domain(
-            state,
+            beacon_state,
             spec.DOMAIN_SHARD_PROPOSER,
-            spec.compute_epoch_of_shard_slot(block.core.slot),
+            spec.compute_epoch_of_shard_slot(block.slot),
         )
     )
 
 
 def build_empty_shard_block(spec,
-                            shard_state,
                             beacon_state,
+                            shard_state,
                             slot,
-                            parent_root,
                             signed=False,
                             full_attestation=False):
     if slot is None:
         slot = shard_state.slot
 
+    previous_beacon_header = deepcopy(beacon_state.latest_block_header)
+    if previous_beacon_header.state_root == spec.Bytes32():
+        previous_beacon_header.state_root = beacon_state.hash_tree_root()
+    beacon_block_root = spec.signing_root(previous_beacon_header)
+
+    previous_block_header = deepcopy(shard_state.latest_block_header)
+    if previous_block_header.state_root == spec.Bytes32():
+        previous_block_header.state_root = shard_state.hash_tree_root()
+    parent_root = signing_root(previous_block_header)
+
     block = spec.ShardBlock(
-        core=spec.ExtendedShardBlockCore(
-            slot=slot,
-            beacon_chain_root=beacon_state.block_roots[beacon_state.slot % spec.SLOTS_PER_HISTORICAL_ROOT],
-            parent_root=parent_root,
-        ),
-        signatures=spec.ShardBlockSignatures(
-            attestation_signature=b'\x00' * 96,
-            proposer_signature=b'\x25' * 96,
-        )
+        shard=shard_state.shard,
+        slot=slot,
+        beacon_block_root=beacon_block_root,
+        parent_root=parent_root,
+        block_size_sum=shard_state.block_size_sum + spec.SHARD_HEADER_SIZE,
     )
 
-    # attestation
     if full_attestation:
-        attester_committee = spec.get_persistent_committee(beacon_state, shard_state.shard, block.core.slot)
-        block.core.attester_bitfield = list(
-            (True,) * len(attester_committee) +
-            (False,) * (spec.TARGET_PERSISTENT_COMMITTEE_SIZE * 2 - len(attester_committee))
-        )
-        block.signatures.attestation_signature = sign_shard_attestation(
-            spec,
-            shard_state,
-            beacon_state,
-            block,
-            participants=attester_committee,
+        shard_committee = spec.get_shard_committee(beacon_state, shard_state.shard, block.slot)
+        block.aggregation_bits = list(
+            (True,) * len(shard_committee) +
+            (False,) * (spec.MAX_PERIOD_COMMITTEE_SIZE * 2 - len(shard_committee))
         )
     else:
-        block.signatures.attestation_signature = sign_shard_attestation(
-            spec,
-            shard_state,
-            beacon_state,
-            block,
-            participants=(),
-        )
+        shard_committee = []
+
+    block.attestations = sign_shard_attestation(
+        spec,
+        beacon_state,
+        shard_state,
+        block,
+        participants=shard_committee,
+    )
 
     if signed:
-        sign_shard_block(spec, beacon_state, block, shard_state.shard)
+        sign_shard_block(spec, beacon_state, shard_state, block)
 
     return block
diff --git a/test_libs/pyspec/eth2spec/test/helpers/phase1/shard_state.py b/test_libs/pyspec/eth2spec/test/helpers/phase1/shard_state.py
new file mode 100644
index 000000000..24240b5fa
--- /dev/null
+++ b/test_libs/pyspec/eth2spec/test/helpers/phase1/shard_state.py
@@ -0,0 +1,18 @@
+from eth2spec.test.helpers.phase1.shard_block import sign_shard_block
+
+
+def configure_shard_state(spec, beacon_state, shard=0):
+    beacon_state.slot = spec.Slot(spec.SHARD_GENESIS_EPOCH * spec.SLOTS_PER_EPOCH)
+    shard_state = spec.get_genesis_shard_state(spec.Shard(shard))
+    shard_state.slot = spec.ShardSlot(spec.SHARD_GENESIS_EPOCH * spec.SHARD_SLOTS_PER_EPOCH)
+    return beacon_state, shard_state
+
+
+def shard_state_transition_and_sign_block(spec, beacon_state, shard_state, block):
+    """
+    Shard state transition via the provided ``block``
+    then package the block with the state root and signature.
+    """
+    spec.shard_state_transition(beacon_state, shard_state, block)
+    block.state_root = shard_state.hash_tree_root()
+    sign_shard_block(spec, beacon_state, shard_state, block)
diff --git a/test_libs/pyspec/eth2spec/test/phase_1/sanity/test_shard_blocks.py b/test_libs/pyspec/eth2spec/test/phase_1/sanity/test_shard_blocks.py
new file mode 100644
index 000000000..51575f2d5
--- /dev/null
+++ b/test_libs/pyspec/eth2spec/test/phase_1/sanity/test_shard_blocks.py
@@ -0,0 +1,177 @@
+from copy import deepcopy
+
+from eth2spec.test.helpers.phase1.shard_block import (
+    build_empty_shard_block,
+    sign_shard_block,
+)
+from eth2spec.test.helpers.phase1.shard_state import (
+    configure_shard_state,
+    shard_state_transition_and_sign_block,
+)
+from eth2spec.test.context import (
+    always_bls,
+    expect_assertion_error,
+    spec_state_test,
+    with_all_phases_except,
+)
+
+
+@with_all_phases_except(['phase0'])
+@spec_state_test
+@always_bls
+def test_process_empty_shard_block(spec, state):
+    beacon_state, shard_state = configure_shard_state(spec, state)
+
+    block = build_empty_shard_block(
+        spec,
+        beacon_state,
+        shard_state,
+        slot=shard_state.slot + 1,
+        signed=True,
+        full_attestation=False,
+    )
+
+    yield 'pre', shard_state
+    yield 'beacon_state', beacon_state
+
+    shard_state_transition_and_sign_block(spec, beacon_state, shard_state, block)
+
+    yield 'blocks', [block]
+    yield 'post', shard_state
+
+
+@with_all_phases_except(['phase0'])
+@spec_state_test
+@always_bls
+def test_process_full_attestation_shard_block(spec, state):
+    beacon_state, shard_state = configure_shard_state(spec, state)
+
+    block = build_empty_shard_block(
+        spec,
+        beacon_state,
+        shard_state,
+        slot=shard_state.slot + 1,
+        signed=True,
+        full_attestation=True,
+    )
+
+    yield 'pre', shard_state
+    yield 'beacon_state', beacon_state
+
+    shard_state_transition_and_sign_block(spec, beacon_state, shard_state, block)
+
+    yield 'blocks', [block]
+    yield 'post', shard_state
+
+
+@with_all_phases_except(['phase0'])
+@spec_state_test
+def test_prev_slot_block_transition(spec, state):
+    beacon_state, shard_state = configure_shard_state(spec, state)
+
+    # Go to clean slot
+    spec.process_shard_slots(shard_state, shard_state.slot + 1)
+    # Make a block for it
+    block = build_empty_shard_block(spec, beacon_state, shard_state, slot=shard_state.slot, signed=True)
+    # Transition to next slot, above block will not be invalid on top of new state.
+    spec.process_shard_slots(shard_state, shard_state.slot + 1)
+
+    yield 'pre', shard_state
+    yield 'beacon_state', beacon_state
+    expect_assertion_error(
+        lambda: spec.shard_state_transition(beacon_state, shard_state, block)
+    )
+    yield 'blocks', [block]
+    yield 'post', None
+
+
+@with_all_phases_except(['phase0'])
+@spec_state_test
+def test_same_slot_block_transition(spec, state):
+    beacon_state, shard_state = configure_shard_state(spec, state)
+
+    # Same slot on top of pre-state, but move out of slot 0 first.
+    spec.process_shard_slots(shard_state, shard_state.slot + 1)
+    block = build_empty_shard_block(spec, beacon_state, shard_state, slot=shard_state.slot, signed=True)
+
+    yield 'pre', shard_state
+    yield 'beacon_state', beacon_state
+
+    shard_state_transition_and_sign_block(spec, beacon_state, shard_state, block)
+
+    yield 'blocks', [block]
+    yield 'post', shard_state
+
+
+@with_all_phases_except(['phase0'])
+@spec_state_test
+def test_invalid_state_root(spec, state):
+    beacon_state, shard_state = configure_shard_state(spec, state)
+
+    spec.process_shard_slots(shard_state, shard_state.slot + 1)
+    block = build_empty_shard_block(spec, beacon_state, shard_state, slot=shard_state.slot)
+    block.state_root = b'\x36' * 32
+    sign_shard_block(spec, beacon_state, shard_state, block)
+
+    yield 'pre', shard_state
+    yield 'beacon_state', beacon_state
+    expect_assertion_error(
+        lambda: spec.shard_state_transition(beacon_state, shard_state, block, validate_state_root=True)
+    )
+    yield 'blocks', [block]
+    yield 'post', None
+
+
+@with_all_phases_except(['phase0'])
+@spec_state_test
+def test_skipped_slots(spec, state):
+    beacon_state, shard_state = configure_shard_state(spec, state)
+
+    block = build_empty_shard_block(spec, beacon_state, shard_state, slot=shard_state.slot + 3, signed=True)
+
+    yield 'pre', shard_state
+    yield 'beacon_state', beacon_state
+
+    shard_state_transition_and_sign_block(spec, beacon_state, shard_state, block)
+
+    yield 'blocks', [block]
+    yield 'post', shard_state
+
+    assert shard_state.slot == block.slot
+    latest_block_header = deepcopy(shard_state.latest_block_header)
+    latest_block_header.state_root = shard_state.hash_tree_root()
+    assert latest_block_header.signing_root() == block.signing_root()
+
+
+@with_all_phases_except(['phase0'])
+@spec_state_test
+def test_empty_shard_period_transition(spec, state):
+    beacon_state, shard_state = configure_shard_state(spec, state)
+
+    # modify some of the deltas to ensure the period transition works properly
+    stub_delta = 10
+    shard_state.newer_committee_positive_deltas[0] = stub_delta
+    shard_state.newer_committee_negative_deltas[0] = stub_delta
+
+    slot = shard_state.slot + spec.SHARD_SLOTS_PER_EPOCH * spec.EPOCHS_PER_SHARD_PERIOD
+    beacon_state.slot = spec.compute_epoch_of_shard_slot(slot) * spec.SLOTS_PER_EPOCH - 4
+    spec.process_slots(beacon_state, spec.compute_epoch_of_shard_slot(slot) * spec.SLOTS_PER_EPOCH)
+
+    # all validators get slashed for not revealing keys
+    # undo this to allow for a block proposal
+    for index in range(len(beacon_state.validators)):
+        beacon_state.validators[index].slashed = False
+    block = build_empty_shard_block(spec, beacon_state, shard_state, slot=slot, signed=True)
+
+    yield 'pre', shard_state
+    yield 'beacon_state', beacon_state
+
+    shard_state_transition_and_sign_block(spec, beacon_state, shard_state, block)
+
+    yield 'blocks', [block]
+    yield 'post', shard_state
+
+    shard_state.older_committee_positive_deltas[0] == stub_delta
+    shard_state.older_committee_negative_deltas[0] == stub_delta
+    shard_state.newer_committee_positive_deltas[0] == 0
+    shard_state.newer_committee_negative_deltas[0] == 0
diff --git a/test_libs/pyspec/eth2spec/test/phase_1/shard_data_chain/test_beacon_attestation.py b/test_libs/pyspec/eth2spec/test/phase_1/shard_data_chain/test_beacon_attestation.py
deleted file mode 100644
index aface905b..000000000
--- a/test_libs/pyspec/eth2spec/test/phase_1/shard_data_chain/test_beacon_attestation.py
+++ /dev/null
@@ -1,48 +0,0 @@
-from eth2spec.test.context import (
-    with_all_phases_except,
-    spec_state_test,
-    always_bls,
-)
-from eth2spec.test.helpers.phase1.shard_block import (
-    build_empty_shard_block,
-)
-from eth2spec.test.helpers.attestations import get_valid_attestation
-
-
-@with_all_phases_except(['phase0'])
-@always_bls
-@spec_state_test
-def test_process_empty_shard_block(spec, state):
-    beacon_state = state
-
-    shard_slot = spec.PHASE_1_FORK_SLOT
-    beacon_state.slot = spec.Slot(spec.PHASE_1_FORK_EPOCH * spec.SLOTS_PER_EPOCH)
-    shard_state = spec.get_default_shard_state(beacon_state, shard=spec.Shard(0))
-    shard_state.slot = shard_slot
-
-    block = build_empty_shard_block(
-        spec,
-        shard_state,
-        beacon_state,
-        slot=shard_slot + 1,
-        parent_root=spec.Hash(),
-        signed=True,
-        full_attestation=True,
-    )
-
-    yield 'pre', shard_state
-    yield 'beacon_state', beacon_state
-    yield 'block', block
-
-    beacon_attestation = get_valid_attestation(spec, beacon_state, signed=True)
-    yield 'beacon_attestation', beacon_attestation
-
-    is_valid_beacon_attestation = spec.is_valid_beacon_attestation(
-        pre_state=shard_state,
-        shard_blocks_or_state_roots=(block,),
-        beacon_state=beacon_state,
-        valid_attestations=set([beacon_attestation]),
-        candidate=beacon_attestation,
-    )
-    assert is_valid_beacon_attestation
-    yield 'is_valid_beacon_attestation', is_valid_beacon_attestation
diff --git a/test_libs/pyspec/eth2spec/test/phase_1/shard_data_chain/test_shard_block.py b/test_libs/pyspec/eth2spec/test/phase_1/shard_data_chain/test_shard_block.py
deleted file mode 100644
index 2bb0232f0..000000000
--- a/test_libs/pyspec/eth2spec/test/phase_1/shard_data_chain/test_shard_block.py
+++ /dev/null
@@ -1,68 +0,0 @@
-from eth2spec.test.helpers.phase1.shard_block import (
-    build_empty_shard_block,
-)
-from eth2spec.test.context import (
-    with_all_phases_except,
-    spec_state_test,
-    always_bls,
-)
-
-
-@with_all_phases_except(['phase0'])
-@always_bls
-@spec_state_test
-def test_process_empty_shard_block(spec, state):
-    beacon_state = state
-
-    shard_slot = spec.PHASE_1_FORK_SLOT
-    beacon_state.slot = spec.Slot(spec.PHASE_1_FORK_EPOCH * spec.SLOTS_PER_EPOCH)
-    shard_state = spec.get_default_shard_state(beacon_state, shard=spec.Shard(0))
-    shard_state.slot = shard_slot
-
-    block = build_empty_shard_block(
-        spec,
-        shard_state,
-        beacon_state,
-        slot=shard_slot + 1,
-        parent_root=spec.Hash(),
-        signed=True,
-        full_attestation=False,
-    )
-
-    yield 'pre', shard_state
-    yield 'beacon_state', beacon_state
-    yield 'block', block
-
-    spec.shard_state_transition(shard_state, beacon_state, block)
-
-    yield 'post', shard_state
-
-
-@with_all_phases_except(['phase0'])
-@always_bls
-@spec_state_test
-def test_process_full_attestation_shard_block(spec, state):
-    beacon_state = state
-
-    shard_slot = spec.PHASE_1_FORK_SLOT
-    beacon_state.slot = spec.Slot(spec.PHASE_1_FORK_EPOCH * spec.SLOTS_PER_EPOCH)
-    shard_state = spec.get_default_shard_state(beacon_state, shard=spec.Shard(0))
-    shard_state.slot = shard_slot
-
-    block = build_empty_shard_block(
-        spec,
-        shard_state,
-        beacon_state,
-        slot=shard_slot + 1,
-        parent_root=spec.Hash(),
-        signed=True,
-        full_attestation=True,
-    )
-
-    yield 'pre', shard_state
-    yield 'beacon_state', beacon_state
-    yield 'block', block
-
-    spec.shard_state_transition(shard_state, beacon_state, block)
-
-    yield 'post', shard_state