diff --git a/src/bin/dolos/eval.rs b/src/bin/dolos/eval.rs
index 19d6ad20..64ebbb9d 100644
--- a/src/bin/dolos/eval.rs
+++ b/src/bin/dolos/eval.rs
@@ -46,7 +46,7 @@ pub fn run(config: &super::Config, args: &Args) -> miette::Result<()> {
 
     for (ref_, output) in utxos.iter() {
         let txin = pallas::ledger::primitives::byron::TxIn::Variant0(
-            pallas::codec::utils::CborWrap((ref_.0.clone(), ref_.1 as u32)),
+            pallas::codec::utils::CborWrap((ref_.0, ref_.1 as u32)),
         );
 
         let key = MultiEraInput::Byron(
diff --git a/src/storage/applydb/mod.rs b/src/storage/applydb/mod.rs
index d5aa0b37..5820b653 100644
--- a/src/storage/applydb/mod.rs
+++ b/src/storage/applydb/mod.rs
@@ -313,12 +313,11 @@ impl ApplyDB {
 
             let utxo_ref = UtxoRef(hash, idx);
 
-            if !utxos.contains_key(&utxo_ref) {
+            if let std::collections::hash_map::Entry::Vacant(e) = utxos.entry(utxo_ref) {
                 let utxo = self
                     .get_utxo(hash, idx)?
                     .ok_or(Error::MissingUtxo(hash, idx))?;
-
-                utxos.insert(utxo_ref, utxo);
+                e.insert(utxo);
             };
         }
 
@@ -434,7 +433,8 @@ impl ApplyDB {
                 prot_magic: self.prot_magic,
                 network_id: self.network_id,
             })
-        } else if block_slot >= 4492800 && block_slot < 40348902 {
+        } else if (4492800..39916974).contains(&block_slot) {
+            // The ShelleyMA era spans from block slot 4492800 to 39916974
             Ok(Environment {
                 prot_params: MultiEraProtParams::Byron(ByronProtParams {
                     fee_policy: FeePolicy {
diff --git a/src/sync/ledger.rs b/src/sync/ledger.rs
index 4fc5ffa2..e04fb0a5 100644
--- a/src/sync/ledger.rs
+++ b/src/sync/ledger.rs
@@ -16,14 +16,14 @@ pub fn execute_phase1_validation(
 ) -> Result<(), WorkerError> {
     let mut utxos = HashMap::new();
     ledger
-        .resolve_inputs_for_block(&block, &mut utxos)
+        .resolve_inputs_for_block(block, &mut utxos)
         .or_panic()?;
 
     let mut utxos2 = UTxOs::new();
 
     for (ref_, output) in utxos.iter() {
         let txin = pallas::ledger::primitives::byron::TxIn::Variant0(
-            pallas::codec::utils::CborWrap((ref_.0.clone(), ref_.1 as u32)),
+            pallas::codec::utils::CborWrap((ref_.0, ref_.1 as u32)),
         );
 
         let key = MultiEraInput::Byron(
@@ -39,7 +39,7 @@ pub fn execute_phase1_validation(
     let env = ledger.get_active_pparams(block.slot()).or_panic()?;
 
     for tx in block.txs().iter() {
-        let res = validate(&tx, &utxos2, &env);
+        let res = validate(tx, &utxos2, &env);
 
         if let Err(err) = res {
             warn!(?err, "validation error");