diff --git a/specs/phase1/validator.md b/specs/phase1/validator.md
index a878b2442..06ec1aa85 100644
--- a/specs/phase1/validator.md
+++ b/specs/phase1/validator.md
@@ -94,9 +94,11 @@ Beacon chain validator assignments to beacon committees and beacon block proposa
 Lookahead for beacon committee assignments operates in the same manner as Phase 0, but committee members must join a shard block pubsub topic in addition to the committee attestation topic.
 
 Specifically _after_ finding stable peers of attestation subnets (see Phase 0) a validator should:
-* Let `shard = compute_shard_from_committee_index(committe_index)`
+* Let `shard = compute_shard_from_committee_index(state, committee_index, slot)`
 * Subscribe to the pubsub topic `shard_{shard}_block` (attestation subnet peers should have this topic available).
 
+TODO: For now, the `state` we pass to `compute_shard_from_committee_index` is the current state without considering `len(state.shard_states)`, i.e., the result from `get_active_shard_count(state)` changes. We should fix it when we have shard count update logic.
+
 ## Beacon chain responsibilities
 
 A validator has two primary responsibilities to the beacon chain: [proposing blocks](#block-proposal) and [creating attestations](#attesting). Proposals happen infrequently, whereas attestations should be created once per epoch.
@@ -136,7 +138,7 @@ Up to `MAX_EARLY_DERIVED_SECRET_REVEALS`, [`EarlyDerivedSecretReveal`](./custody
 Exactly `MAX_SHARDS` [`ShardTransition`](./beacon-chain.md#shardtransition) objects are included in the block. Default each to an empty `ShardTransition()`. Then for each committee assigned to the slot with an associated `committee_index` and `shard`, set `shard_transitions[shard] = full_transitions[winning_root]` if the committee had enough weight to form a crosslink this slot.
 
 Specifically:
-* Call `shards, winning_roots = get_shard_winning_roots(state, block.slot, block.body.attestations)`
+* Call `shards, winning_roots = get_shard_winning_roots(state, block.body.attestations)`
 * Let `full_transitions` be a dictionary mapping from the `shard_transition_root`s found in `attestations` to the corresponding full `ShardTransition`
 * Then for each `shard` and `winning_root` in `zip(shards, winning_roots)` set `shard_transitions[shard] = full_transitions[winning_root]`
 
@@ -185,7 +187,7 @@ def get_shard_winning_roots(state: BeaconState,
 
 ##### Light client fields
 
-First retrieve `best_aggregate` from `get_best_light_client_aggregate` where `aggregates` is a list of valid aggregated `LightClientVote`s for the previous slot.
+First retrieve `best_aggregate` from `get_best_light_client_aggregate(block, aggregates)` where `aggregates` is a list of valid aggregated `LightClientVote`s for the previous slot.
 
 Then:
 * Set `light_client_bits = best_aggregate.aggregation_bits`