diff --git a/beacon_chain/el/el_manager.nim b/beacon_chain/el/el_manager.nim
index d8684372e..680a9fa59 100644
--- a/beacon_chain/el/el_manager.nim
+++ b/beacon_chain/el/el_manager.nim
@@ -670,7 +670,7 @@ proc popFirst(chain: var Eth1Chain) =
   chain.blocksByHash.del removed.hash.asBlockHash
   eth1_chain_len.set chain.blocks.len.int64
 
-func getDepositsRoot*(m: DepositsMerkleizer): Eth2Digest =
+func getDepositsRoot*(m: var DepositsMerkleizer): Eth2Digest =
   mixInLength(m.getFinalHash, int m.totalChunks)
 
 proc addBlock*(chain: var Eth1Chain, newBlock: Eth1Block) =
@@ -1783,7 +1783,7 @@ proc getBlockProposalData*(chain: var Eth1Chain,
           deposits.add data
         depositRoots.add hash_tree_root(data)
 
-      var scratchMerkleizer = copy chain.finalizedDepositsMerkleizer
+      var scratchMerkleizer = chain.finalizedDepositsMerkleizer
       if chain.advanceMerkleizer(scratchMerkleizer, stateDepositIdx):
         let proofs = scratchMerkleizer.addChunksAndGenMerkleProofs(depositRoots)
         for i in 0 ..< totalDepositsInNewBlock:
@@ -1844,7 +1844,7 @@ proc init*(T: type Eth1Chain,
     cfg: cfg,
     finalizedBlockHash: finalizedBlockHash,
     finalizedDepositsMerkleizer: m,
-    headMerkleizer: copy m)
+    headMerkleizer: m)
 
 proc new*(T: type ELManager,
           cfg: RuntimeConfig,
@@ -1877,7 +1877,7 @@ proc safeCancel(fut: var Future[void]) =
 func clear(chain: var Eth1Chain) =
   chain.blocks.clear()
   chain.blocksByHash.clear()
-  chain.headMerkleizer = copy chain.finalizedDepositsMerkleizer
+  chain.headMerkleizer = chain.finalizedDepositsMerkleizer
   chain.hasConsensusViolation = false
 
 proc doStop(m: ELManager) {.async.} =
diff --git a/beacon_chain/spec/deposit_snapshots.nim b/beacon_chain/spec/deposit_snapshots.nim
index e9907e39d..a905edfb1 100644
--- a/beacon_chain/spec/deposit_snapshots.nim
+++ b/beacon_chain/spec/deposit_snapshots.nim
@@ -1,3 +1,12 @@
+# beacon_chain
+# Copyright (c) 2018-2023 Status Research & Development GmbH
+# Licensed and distributed under either of
+#   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
+#   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
+# at your option. This file may not be copied, modified, or distributed except according to those terms.
+
+{.push raises: [].}
+
 from stew/objects import isZeroMemory
 
 import ./eth2_merkleization
@@ -35,11 +44,11 @@ template getDepositCountU64*(d: OldDepositContractSnapshot |
 
 func getDepositRoot*(d: OldDepositContractSnapshot |
                         DepositTreeSnapshot): Eth2Digest =
-  let merk = DepositsMerkleizer.init(d.depositContractState)
+  var merk = DepositsMerkleizer.init(d.depositContractState)
   let hash = merk.getFinalHash()
   # TODO: mixInLength should accept unsigned int instead of int as
   # this right now cuts in half the theoretical number of deposits.
-  return mixInLength(hash, int(merk.totalChunks))
+  return mixInLength(hash, int(merk.getChunkCount()))
 
 func isValid*(d: DepositTreeSnapshot, wantedDepositRoot: Eth2Digest): bool =
   ## `isValid` requires the snapshot to be self-consistent and
diff --git a/vendor/nim-ssz-serialization b/vendor/nim-ssz-serialization
index a5767c1b4..edf07d4f7 160000
--- a/vendor/nim-ssz-serialization
+++ b/vendor/nim-ssz-serialization
@@ -1 +1 @@
-Subproject commit a5767c1b4992dca3e5bd72557aadd4df0f183bf8
+Subproject commit edf07d4f7e0cb27afd207aa183c23cf448082d1b