diff --git a/beacon_node/beacon_chain/src/builder.rs b/beacon_node/beacon_chain/src/builder.rs
index a0ebcc8db9..1a66d80a6a 100644
--- a/beacon_node/beacon_chain/src/builder.rs
+++ b/beacon_node/beacon_chain/src/builder.rs
@@ -830,12 +830,7 @@ where
         })?;
 
         let migrator_config = self.store_migrator_config.unwrap_or_default();
-        let store_migrator = BackgroundMigrator::new(
-            store.clone(),
-            migrator_config,
-            genesis_block_root,
-            log.clone(),
-        );
+        let store_migrator = BackgroundMigrator::new(store.clone(), migrator_config, log.clone());
 
         if let Some(slot) = slot_clock.now() {
             validator_monitor.process_valid_state(
diff --git a/beacon_node/beacon_chain/src/migrate.rs b/beacon_node/beacon_chain/src/migrate.rs
index bcecb7fce8..09609c8b3b 100644
--- a/beacon_node/beacon_chain/src/migrate.rs
+++ b/beacon_node/beacon_chain/src/migrate.rs
@@ -1,6 +1,4 @@
-use crate::beacon_chain::BEACON_CHAIN_DB_KEY;
 use crate::errors::BeaconChainError;
-use crate::persisted_beacon_chain::{PersistedBeaconChain, DUMMY_CANONICAL_HEAD_BLOCK_ROOT};
 use crate::summaries_dag::{
     self, BlockSummariesDAG, DAGBlockSummary, DAGStateSummary, StateSummariesDAG,
 };
@@ -13,7 +11,7 @@ use std::sync::{mpsc, Arc};
 use std::thread;
 use std::time::{Duration, SystemTime, UNIX_EPOCH};
 use store::hot_cold_store::{migrate_database, HotColdDBError};
-use store::{DBColumn, Error, HotStateSummary, ItemStore, StoreItem, StoreOp};
+use store::{DBColumn, Error, HotStateSummary, ItemStore, StoreOp};
 pub use store::{HotColdDB, MemoryStore};
 use types::{BeaconState, BeaconStateHash, Checkpoint, Epoch, EthSpec, Hash256, Slot};
 
@@ -39,8 +37,6 @@ pub struct BackgroundMigrator<E: EthSpec, Hot: ItemStore<E>, Cold: ItemStore<E>>
     prev_migration: Arc<Mutex<PrevMigration>>,
     #[allow(clippy::type_complexity)]
     tx_thread: Option<Mutex<(mpsc::Sender<Notification>, thread::JoinHandle<()>)>>,
-    /// Genesis block root, for persisting the `PersistedBeaconChain`.
-    genesis_block_root: Hash256,
     log: Logger,
 }
 
@@ -132,17 +128,11 @@ pub struct FinalizationNotification {
     finalized_state_root: BeaconStateHash,
     finalized_checkpoint: Checkpoint,
     prev_migration: Arc<Mutex<PrevMigration>>,
-    genesis_block_root: Hash256,
 }
 
 impl<E: EthSpec, Hot: ItemStore<E>, Cold: ItemStore<E>> BackgroundMigrator<E, Hot, Cold> {
     /// Create a new `BackgroundMigrator` and spawn its thread if necessary.
-    pub fn new(
-        db: Arc<HotColdDB<E, Hot, Cold>>,
-        config: MigratorConfig,
-        genesis_block_root: Hash256,
-        log: Logger,
-    ) -> Self {
+    pub fn new(db: Arc<HotColdDB<E, Hot, Cold>>, config: MigratorConfig, log: Logger) -> Self {
         // Estimate last migration run from DB split slot.
         let prev_migration = Arc::new(Mutex::new(PrevMigration {
             epoch: db.get_split_slot().epoch(E::slots_per_epoch()),
@@ -157,7 +147,6 @@ impl<E: EthSpec, Hot: ItemStore<E>, Cold: ItemStore<E>> BackgroundMigrator<E, Ho
             db,
             tx_thread,
             prev_migration,
-            genesis_block_root,
             log,
         }
     }
@@ -176,7 +165,6 @@ impl<E: EthSpec, Hot: ItemStore<E>, Cold: ItemStore<E>> BackgroundMigrator<E, Ho
             finalized_state_root,
             finalized_checkpoint,
             prev_migration: self.prev_migration.clone(),
-            genesis_block_root: self.genesis_block_root,
         };
 
         // Send to background thread if configured, otherwise run in foreground.
@@ -361,7 +349,6 @@ impl<E: EthSpec, Hot: ItemStore<E>, Cold: ItemStore<E>> BackgroundMigrator<E, Ho
             finalized_state_root.into(),
             &finalized_state,
             notif.finalized_checkpoint,
-            notif.genesis_block_root,
             log,
         ) {
             Ok(PruningOutcome::Successful {
@@ -472,7 +459,6 @@ impl<E: EthSpec, Hot: ItemStore<E>, Cold: ItemStore<E>> BackgroundMigrator<E, Ho
         new_finalized_state_hash: Hash256,
         new_finalized_state: &BeaconState<E>,
         new_finalized_checkpoint: Checkpoint,
-        genesis_block_root: Hash256,
         log: &Logger,
     ) -> Result<PruningOutcome, BeaconChainError> {
         let new_finalized_slot = new_finalized_checkpoint
@@ -532,7 +518,7 @@ impl<E: EthSpec, Hot: ItemStore<E>, Cold: ItemStore<E>> BackgroundMigrator<E, Ho
                 .iter()
                 .map(|block_root| {
                     let block = store
-                        .get_blinded_block(&block_root)?
+                        .get_blinded_block(block_root)?
                         .ok_or(PruningError::MissingBlindedBlock(*block_root))?;
                     Ok((
                         *block_root,
diff --git a/beacon_node/beacon_chain/src/summaries_dag.rs b/beacon_node/beacon_chain/src/summaries_dag.rs
index 93ed6f2bdb..11da1dce4e 100644
--- a/beacon_node/beacon_chain/src/summaries_dag.rs
+++ b/beacon_node/beacon_chain/src/summaries_dag.rs
@@ -283,7 +283,7 @@ impl BlockSummariesDAG {
 
 #[cfg(test)]
 mod tests {
-    use super::{BlockSummariesDAG, DAGStateSummaryV22, Error, StateSummariesDAG};
+    use super::{BlockSummariesDAG, DAGBlockSummary, DAGStateSummaryV22, Error, StateSummariesDAG};
     use bls::FixedBytesExtended;
     use std::collections::HashMap;
     use types::{Hash256, Slot};
@@ -292,6 +292,13 @@ mod tests {
         Hash256::from_low_u64_le(n)
     }
 
+    fn block_with_parent(parent_root: Hash256) -> DAGBlockSummary {
+        DAGBlockSummary {
+            slot: Slot::new(0),
+            parent_root,
+        }
+    }
+
     #[test]
     fn new_from_v22_empty() {
         StateSummariesDAG::new_from_v22(vec![], HashMap::new(), Hash256::ZERO).unwrap();
@@ -321,9 +328,8 @@ mod tests {
         let root_1 = root(1);
         let root_2 = root(2);
         let root_3 = root(3);
-        //                                 (child, parent)
-        let parents = HashMap::from_iter([(root_1, root_2)]);
-        let dag = BlockSummariesDAG::new(parents);
+        let parents = vec![(root_1, block_with_parent(root_2))];
+        let dag = BlockSummariesDAG::new(&parents);
 
         // root 1 is known and has no childs
         assert_eq!(