diff --git a/test_libs/pyspec/eth2spec/test/context.py b/test_libs/pyspec/eth2spec/test/context.py
index b2e67d761..a9eaea349 100644
--- a/test_libs/pyspec/eth2spec/test/context.py
+++ b/test_libs/pyspec/eth2spec/test/context.py
@@ -28,6 +28,17 @@ def expect_assertion_error(fn):
         raise AssertionError('expected an assertion error, but got none.')
 
 
+def never_bls(fn):
+    """
+    Decorator to apply on ``bls_switch`` decorator to force BLS de-activation. Useful to mark tests as BLS-ignorant.
+    """
+    def entry(*args, **kw):
+        # override bls setting
+        kw['bls_active'] = False
+        fn(*args, **kw)
+    return entry
+
+
 def always_bls(fn):
     """
     Decorator to apply on ``bls_switch`` decorator to force BLS activation. Useful to mark tests as BLS-dependent.
diff --git a/test_libs/pyspec/eth2spec/test/helpers/transfers.py b/test_libs/pyspec/eth2spec/test/helpers/transfers.py
index 37547bf97..2045f48ad 100644
--- a/test_libs/pyspec/eth2spec/test/helpers/transfers.py
+++ b/test_libs/pyspec/eth2spec/test/helpers/transfers.py
@@ -1,7 +1,7 @@
 # Access constants from spec pkg reference.
 import eth2spec.phase0.spec as spec
 
-from eth2spec.phase0.spec import get_current_epoch, get_active_validator_indices, Transfer, ZERO_HASH, get_domain
+from eth2spec.phase0.spec import get_current_epoch, get_active_validator_indices, Transfer, get_domain
 from eth2spec.test.helpers.keys import pubkeys, privkeys
 from eth2spec.test.helpers.state import get_balance
 from eth2spec.utils.bls import bls_sign
@@ -30,7 +30,6 @@ def get_valid_transfer(state, slot=None, sender_index=None, amount=None, fee=Non
         fee=fee,
         slot=slot,
         pubkey=transfer_pubkey,
-        signature=ZERO_HASH,
     )
     if signed:
         sign_transfer(state, transfer, transfer_privkey)
diff --git a/test_libs/pyspec/eth2spec/test/test_finality.py b/test_libs/pyspec/eth2spec/test/test_finality.py
index 26900340d..56f65eca9 100644
--- a/test_libs/pyspec/eth2spec/test/test_finality.py
+++ b/test_libs/pyspec/eth2spec/test/test_finality.py
@@ -4,11 +4,10 @@ import eth2spec.phase0.spec as spec
 from eth2spec.phase0.state_transition import (
     state_transition,
 )
-from .context import spec_state_test
+from .context import spec_state_test, never_bls
 from .helpers.state import next_epoch
 from .helpers.block import build_empty_block_for_next_slot, apply_empty_block
 from .helpers.attestations import (
-    fill_aggregate_attestation,
     get_current_epoch,
     get_epoch_start_slot,
     get_valid_attestation,
@@ -66,6 +65,7 @@ def next_epoch_with_attestations(state,
     return state, blocks, post_state
 
 
+@never_bls
 @spec_state_test
 def test_finality_rule_4(state):
     yield 'pre', state
@@ -93,6 +93,7 @@ def test_finality_rule_4(state):
     yield 'post', state
 
 
+@never_bls
 @spec_state_test
 def test_finality_rule_1(state):
     # get past first two epochs that finality does not run on
@@ -122,6 +123,7 @@ def test_finality_rule_1(state):
     yield 'post', state
 
 
+@never_bls
 @spec_state_test
 def test_finality_rule_2(state):
     # get past first two epochs that finality does not run on
@@ -153,6 +155,7 @@ def test_finality_rule_2(state):
     yield 'post', state
 
 
+@never_bls
 @spec_state_test
 def test_finality_rule_3(state):
     """
diff --git a/test_libs/pyspec/eth2spec/test/test_sanity.py b/test_libs/pyspec/eth2spec/test/test_sanity.py
index 5e3b32416..27b40f93b 100644
--- a/test_libs/pyspec/eth2spec/test/test_sanity.py
+++ b/test_libs/pyspec/eth2spec/test/test_sanity.py
@@ -1,7 +1,7 @@
 from copy import deepcopy
 
-from py_ecc import bls
 import eth2spec.phase0.spec as spec
+from eth2spec.utils.bls import bls_sign
 
 from eth2spec.utils.minimal_ssz import signing_root
 from eth2spec.phase0.spec import (
@@ -24,7 +24,7 @@ from .helpers.state import (
     get_state_root
 )
 from .helpers.transfers import get_valid_transfer
-from .helpers.block import build_empty_block_for_next_slot
+from .helpers.block import build_empty_block_for_next_slot, sign_block
 from .helpers.keys import (
     privkeys,
     pubkeys,
@@ -58,7 +58,7 @@ def test_empty_block_transition(state):
 
     yield 'pre', state
 
-    block = build_empty_block_for_next_slot(state)
+    block = build_empty_block_for_next_slot(state, signed=True)
     yield 'blocks', [block], [spec.BeaconBlock]
 
     state_transition(state, block)
@@ -73,8 +73,9 @@ def test_skipped_slots(state):
     pre_slot = state.slot
     yield 'pre', state
 
-    block = build_empty_block_for_next_slot(state)
+    block = build_empty_block_for_next_slot(state, signed=False)
     block.slot += 3
+    sign_block(state, block)
     yield 'blocks', [block], [spec.BeaconBlock]
 
     state_transition(state, block)
@@ -90,8 +91,9 @@ def test_empty_epoch_transition(state):
     pre_slot = state.slot
     yield 'pre', state
 
-    block = build_empty_block_for_next_slot(state)
+    block = build_empty_block_for_next_slot(state, signed=False)
     block.slot += spec.SLOTS_PER_EPOCH
+    sign_block(state, block)
     yield 'blocks', [block], [spec.BeaconBlock]
 
     state_transition(state, block)
@@ -289,7 +291,7 @@ def test_voluntary_exit(state):
         epoch=get_current_epoch(state),
         validator_index=validator_index,
     )
-    voluntary_exit.signature = bls.sign(
+    voluntary_exit.signature = bls_sign(
         message_hash=signing_root(voluntary_exit),
         privkey=privkeys[validator_index],
         domain=get_domain(