diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md
index d9454fff1..732cec31e 100644
--- a/specs/core/0_beacon-chain.md
+++ b/specs/core/0_beacon-chain.md
@@ -1036,6 +1036,7 @@ def initialize_beacon_state_from_eth1(eth1_block_hash: Hash,
         genesis_time=eth1_timestamp - eth1_timestamp % SECONDS_PER_DAY + 2 * SECONDS_PER_DAY,
         eth1_data=Eth1Data(block_hash=eth1_block_hash, deposit_count=len(deposits)),
         latest_block_header=BeaconBlockHeader(body_root=hash_tree_root(BeaconBlockBody())),
+        randao_mixes=[eth1_block_hash] * EPOCHS_PER_HISTORICAL_VECTOR,  # Seed RANDAO with Eth1 entropy
     )
 
     # Process deposits
diff --git a/test_libs/pyspec/eth2spec/test/helpers/genesis.py b/test_libs/pyspec/eth2spec/test/helpers/genesis.py
index 9e3c77b7b..7e747e34e 100644
--- a/test_libs/pyspec/eth2spec/test/helpers/genesis.py
+++ b/test_libs/pyspec/eth2spec/test/helpers/genesis.py
@@ -19,15 +19,17 @@ def build_mock_validator(spec, i: int, balance: int):
 def create_genesis_state(spec, num_validators):
     deposit_root = b'\x42' * 32
 
+    eth1_block_hash = b'\xda' * 32
     state = spec.BeaconState(
         genesis_time=0,
         eth1_deposit_index=num_validators,
         eth1_data=spec.Eth1Data(
             deposit_root=deposit_root,
             deposit_count=num_validators,
-            block_hash=spec.Hash(),
+            block_hash=eth1_block_hash,
         ),
         latest_block_header=spec.BeaconBlockHeader(body_root=spec.hash_tree_root(spec.BeaconBlockBody())),
+        randao_mixes=[eth1_block_hash] * spec.EPOCHS_PER_HISTORICAL_VECTOR,
     )
 
     # We "hack" in the initial validators,
diff --git a/test_libs/pyspec/eth2spec/test/sanity/test_blocks.py b/test_libs/pyspec/eth2spec/test/sanity/test_blocks.py
index 5e919120d..bffb1c1fc 100644
--- a/test_libs/pyspec/eth2spec/test/sanity/test_blocks.py
+++ b/test_libs/pyspec/eth2spec/test/sanity/test_blocks.py
@@ -475,6 +475,8 @@ def test_eth1_data_votes_no_consensus(spec, state):
     if spec.SLOTS_PER_ETH1_VOTING_PERIOD > 16:
         return
 
+    pre_eth1_hash = state.eth1_data.block_hash
+
     offset_block = build_empty_block(spec, state, slot=spec.SLOTS_PER_ETH1_VOTING_PERIOD - 1)
     sign_block(spec, state, offset_block)
     state_transition_and_sign_block(spec, state, offset_block)
@@ -494,7 +496,7 @@ def test_eth1_data_votes_no_consensus(spec, state):
         blocks.append(block)
 
     assert len(state.eth1_data_votes) == spec.SLOTS_PER_ETH1_VOTING_PERIOD
-    assert state.eth1_data.block_hash == b'\x00' * 32
+    assert state.eth1_data.block_hash == pre_eth1_hash
 
     yield 'blocks', blocks
     yield 'post', state