diff --git a/core/state.go b/core/state.go
index 27c20f0572..3b9d080ec5 100644
--- a/core/state.go
+++ b/core/state.go
@@ -142,8 +142,7 @@ func (s *State) globalTrie(bucket db.Bucket, newTrie trie.NewTrieFunc) (*trie.Tr
 	var rootKey *trie.BitArray // TODO: use value instead of pointer
 	err := s.txn.Get(rootKeyDBKey, func(val []byte) error {
 		rootKey = new(trie.BitArray)
-		rootKey.UnmarshalBinary(val)
-		return nil
+		return rootKey.UnmarshalBinary(val)
 	})
 
 	// if some error other than "not found"
diff --git a/core/trie/bitarray.go b/core/trie/bitarray.go
index b2bf952693..d1d28eab73 100644
--- a/core/trie/bitarray.go
+++ b/core/trie/bitarray.go
@@ -38,7 +38,8 @@ func NewBitArray(length uint8, val uint64) BitArray {
 // Returns the felt representation of the bit array.
 func (b *BitArray) Felt() felt.Felt {
 	var f felt.Felt
-	f.SetBytes(b.Bytes())
+	bt := b.Bytes()
+	f.SetBytes(bt[:])
 	return f
 }
 
@@ -47,7 +48,7 @@ func (b *BitArray) Len() uint8 {
 }
 
 // Returns the bytes representation of the bit array in big endian format
-func (b *BitArray) Bytes() []byte {
+func (b *BitArray) Bytes() [32]byte {
 	var res [32]byte
 
 	binary.BigEndian.PutUint64(res[0:8], b.words[3])
@@ -55,7 +56,7 @@ func (b *BitArray) Bytes() []byte {
 	binary.BigEndian.PutUint64(res[16:24], b.words[1])
 	binary.BigEndian.PutUint64(res[24:32], b.words[0])
 
-	return res[:]
+	return res
 }
 
 // Sets the bit array to the least significant 'n' bits of x.
@@ -512,15 +513,17 @@ func (b *BitArray) Copy() BitArray {
 // Returns the encoded string representation of the bit array.
 func (b *BitArray) EncodedString() string {
 	var res []byte
+	bt := b.Bytes()
 	res = append(res, b.len)
-	res = append(res, b.Bytes()...)
+	res = append(res, bt[:]...)
 	return string(res)
 }
 
 // Returns a string representation of the bit array.
 // This is typically used for logging or debugging.
 func (b *BitArray) String() string {
-	return fmt.Sprintf("(%d) %s", b.len, hex.EncodeToString(b.Bytes()))
+	bt := b.Bytes()
+	return fmt.Sprintf("(%d) %s", b.len, hex.EncodeToString(bt[:]))
 }
 
 func (b *BitArray) setFelt(f *felt.Felt) {
diff --git a/core/trie/bitarray_test.go b/core/trie/bitarray_test.go
index 123ed52441..4786eee2e6 100644
--- a/core/trie/bitarray_test.go
+++ b/core/trie/bitarray_test.go
@@ -97,7 +97,7 @@ func TestBytes(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			got := tt.ba.Bytes()
-			if !bytes.Equal(got, tt.want[:]) {
+			if !bytes.Equal(got[:], tt.want[:]) {
 				t.Errorf("BitArray.Bytes() = %v, want %v", got, tt.want)
 			}
 
diff --git a/migration/migration_pkg_test.go b/migration/migration_pkg_test.go
index 9618ce4d6f..2b632d607a 100644
--- a/migration/migration_pkg_test.go
+++ b/migration/migration_pkg_test.go
@@ -261,10 +261,7 @@ func TestMigrateTrieRootKeysFromBitsetToTrieKeys(t *testing.T) {
 	require.NoError(t, migrateTrieRootKeysFromBitsetToTrieKeys(memTxn, key, bsBytes, &utils.Mainnet))
 
 	var trieKey trie.BitArray
-	err = memTxn.Get(key, func(data []byte) error {
-		trieKey.UnmarshalBinary(data)
-		return nil
-	})
+	err = memTxn.Get(key, trieKey.UnmarshalBinary)
 	require.NoError(t, err)
 	require.Equal(t, bs.Len(), uint(trieKey.Len()))
 	require.Equal(t, felt.Zero, trieKey.Felt())