diff --git a/specs/phase1/beacon-chain.md b/specs/phase1/beacon-chain.md
index 759687a2f..4fe0316f3 100644
--- a/specs/phase1/beacon-chain.md
+++ b/specs/phase1/beacon-chain.md
@@ -773,11 +773,11 @@ def validate_attestation(state: BeaconState, attestation: Attestation) -> None:
         shard = compute_shard_from_committee_index(state, data.index, data.slot)
         assert data.shard == shard
         # NOTE: We currently set `PHASE_1_FORK_SLOT` to `GENESIS_SLOT` for test vectors.
-        if data.slot == PHASE_1_FORK_SLOT:
-            assert data.shard_transition_root == hash_tree_root(ShardTransition())
-        else:
+        if data.slot > PHASE_1_FORK_SLOT:
             # On-time attestations should have a non-empty shard transition root
             assert data.shard_transition_root != hash_tree_root(ShardTransition())
+        else:
+            assert data.shard_transition_root == hash_tree_root(ShardTransition())
     # Type 2: no shard transition
     else:
         # Ensure delayed attestation
@@ -981,7 +981,7 @@ def process_shard_transitions(state: BeaconState,
                               shard_transitions: Sequence[ShardTransition],
                               attestations: Sequence[Attestation]) -> None:
     # NOTE: We currently set `PHASE_1_FORK_SLOT` to `GENESIS_SLOT` for test vectors.
-    if compute_previous_slot(state.slot) != PHASE_1_FORK_SLOT:
+    if compute_previous_slot(state.slot) > PHASE_1_FORK_SLOT:
         # Process crosslinks
         process_crosslinks(state, shard_transitions, attestations)