diff --git a/specs/phase1/beacon-chain.md b/specs/phase1/beacon-chain.md
index 9a07e0a77..3bb01e262 100644
--- a/specs/phase1/beacon-chain.md
+++ b/specs/phase1/beacon-chain.md
@@ -478,7 +478,7 @@ def get_online_validator_indices(state: BeaconState) -> Set[ValidatorIndex]:
 ```python
 def get_shard_committee(beacon_state: BeaconState, epoch: Epoch, shard: Shard) -> Sequence[ValidatorIndex]:
     source_epoch = epoch - epoch % SHARD_COMMITTEE_PERIOD
-    if source_epoch > 0:
+    if source_epoch >= SHARD_COMMITTEE_PERIOD:
         source_epoch -= SHARD_COMMITTEE_PERIOD
     active_validator_indices = get_active_validator_indices(beacon_state, source_epoch)
     seed = get_seed(beacon_state, source_epoch, DOMAIN_SHARD_COMMITTEE)
@@ -496,7 +496,7 @@ def get_shard_committee(beacon_state: BeaconState, epoch: Epoch, shard: Shard) -
 ```python
 def get_light_client_committee(beacon_state: BeaconState, epoch: Epoch) -> Sequence[ValidatorIndex]:
     source_epoch = epoch - epoch % LIGHT_CLIENT_COMMITTEE_PERIOD
-    if source_epoch > 0:
+    if source_epoch >= LIGHT_CLIENT_COMMITTEE_PERIOD:
         source_epoch -= LIGHT_CLIENT_COMMITTEE_PERIOD
     active_validator_indices = get_active_validator_indices(beacon_state, source_epoch)
     seed = get_seed(beacon_state, source_epoch, DOMAIN_LIGHT_CLIENT)
diff --git a/specs/phase1/shard-transition.md b/specs/phase1/shard-transition.md
index 36b3b80ab..29c3e1b8f 100644
--- a/specs/phase1/shard-transition.md
+++ b/specs/phase1/shard-transition.md
@@ -260,7 +260,7 @@ def get_shard_state_transition_result(
 
 ### Make attestations
 
-Suppose you are a committee member on shard `shard` at slot `current_slot` and you have received shard blocks `shard_blocks` since the latest successful crosslink for `shard` into the beacon chain. Let `state` be the head beacon state you are building on, and let `QUARTER_PERIOD = SECONDS_PER_SLOT // 4`. `2 * QUARTER_PERIOD` seconds into slot `current_slot`, run `get_shard_transition(beacon_state, shard, shard_blocks)` to get `shard_transition`.
+Suppose you are a committee member on shard `shard` at slot `current_slot` and you have received shard blocks `shard_blocks` since the latest successful crosslink for `shard` into the beacon chain. Let `beacon_state` be the head beacon state you are building on, and let `QUARTER_PERIOD = SECONDS_PER_SLOT // 4`. `2 * QUARTER_PERIOD` seconds into slot `current_slot`, run `get_shard_transition(beacon_state, shard, shard_blocks)` to get `shard_transition`.
 
 ```python
 def get_shard_transition(beacon_state: BeaconState,