diff --git a/src/miner.h b/src/miner.h
--- a/src/miner.h
+++ b/src/miner.h
@@ -186,6 +186,8 @@
 /** Generate a new block, without valid proof-of-work */
 class BlockAssembler {
 private:
+    typedef std::unordered_set<TxId, SaltedTxidHasher> TxIdSet;
+
     // The constructed block template
     std::unique_ptr<CBlockTemplate> pblocktemplate;
     // A convenience pointer that always refers to the CBlock in pblocktemplate
@@ -200,7 +202,7 @@
     uint64_t nBlockTx;
     uint64_t nBlockSigOps;
     Amount nFees;
-    CTxMemPool::setEntries inBlock;
+    TxIdSet inBlock;
 
     // Chain context for the block
     int nHeight;
@@ -263,7 +265,7 @@
      * or if the transaction's cached data in mapTx is incorrect. */
     bool SkipMapTxEntry(CTxMemPool::txiter it,
                         indexed_modified_transaction_set &mapModifiedTx,
-                        CTxMemPool::setEntries &failedTx);
+                        const TxIdSet &failedTx);
     /** Sort the package in an order that is valid to appear in a block */
     void SortForBlock(const CTxMemPool::setEntries &package,
                       CTxMemPool::txiter entry,
@@ -273,6 +275,8 @@
      * of updated descendants. */
     int UpdatePackagesForAdded(const CTxMemPool::setEntries &alreadyAdded,
                                indexed_modified_transaction_set &mapModifiedTx);
+    int UpdatePackagesForAdded(const TxIdSet &alreadyAdded,
+                               indexed_modified_transaction_set &mapModifiedTx);
 };
 
 /** Modify the extranonce in a block */
diff --git a/src/miner.cpp b/src/miner.cpp
--- a/src/miner.cpp
+++ b/src/miner.cpp
@@ -253,7 +253,7 @@
 
 bool BlockAssembler::isStillDependent(CTxMemPool::txiter iter) {
     for (CTxMemPool::txiter parent : mempool->GetMemPoolParents(iter)) {
-        if (!inBlock.count(parent)) {
+        if (!inBlock.count(parent->GetTx().GetId())) {
             return true;
         }
     }
@@ -264,7 +264,7 @@
     for (CTxMemPool::setEntries::iterator iit = testSet.begin();
          iit != testSet.end();) {
         // Only test txs not already in the block.
-        if (inBlock.count(*iit)) {
+        if (inBlock.count((*iit)->GetTx().GetId())) {
             testSet.erase(iit++);
         } else {
             iit++;
@@ -365,7 +365,7 @@
     ++nBlockTx;
     nBlockSigOps += iter->GetSigOpCount();
     nFees += iter->GetFee();
-    inBlock.insert(iter);
+    inBlock.insert(iter->GetTx().GetId());
 
     bool fPrintPriority =
         gArgs.GetBoolArg("-printpriority", DEFAULT_PRINTPRIORITY);
@@ -380,6 +380,17 @@
     }
 }
 
+// TODO: Temporary adapter, delete this eventually.
+int BlockAssembler::UpdatePackagesForAdded(
+    const TxIdSet &alreadyAdded,
+    indexed_modified_transaction_set &mapModifiedTx) {
+    CTxMemPool::setEntries entries;
+    for (const TxId &id : alreadyAdded) {
+        entries.insert(mempool->mapTx.find(id));
+    }
+    return UpdatePackagesForAdded(entries, mapModifiedTx);
+}
+
 int BlockAssembler::UpdatePackagesForAdded(
     const CTxMemPool::setEntries &alreadyAdded,
     indexed_modified_transaction_set &mapModifiedTx) {
@@ -421,9 +432,11 @@
 // be using cached size/sigops/fee values that are not actually correct.
 bool BlockAssembler::SkipMapTxEntry(
     CTxMemPool::txiter it, indexed_modified_transaction_set &mapModifiedTx,
-    CTxMemPool::setEntries &failedTx) {
+    const TxIdSet &failedTx) {
     assert(it != mempool->mapTx.end());
-    return mapModifiedTx.count(it) || inBlock.count(it) || failedTx.count(it);
+    const TxId &txId = it->GetTx().GetId();
+    return mapModifiedTx.count(it) || inBlock.count(txId) ||
+           failedTx.count(txId);
 }
 
 void BlockAssembler::SortForBlock(
@@ -463,7 +476,7 @@
     // some of their txs are already in the block.
     indexed_modified_transaction_set mapModifiedTx;
     // Keep track of entries that failed inclusion, to avoid duplicate work.
-    CTxMemPool::setEntries failedTx;
+    TxIdSet failedTx;
 
     // Start by adding all descendants of previously added txs to mapModifiedTx
     // and modifying them for their already included ancestors.
@@ -516,7 +529,7 @@
 
         // We skip mapTx entries that are inBlock, and mapModifiedTx shouldn't
         // contain anything that is inBlock.
-        assert(!inBlock.count(iter));
+        assert(!inBlock.count(iter->GetTx().GetId()));
 
         uint64_t packageSize = iter->GetSizeWithAncestors();
         Amount packageFees = iter->GetModFeesWithAncestors();
@@ -538,7 +551,7 @@
                 // must erase failed entries so that we can consider the next
                 // best entry on the next loop iteration
                 mapModifiedTx.get<ancestor_score>().erase(modit);
-                failedTx.insert(iter);
+                failedTx.insert(iter->GetTx().GetId());
             }
 
             ++nConsecutiveFailed;
@@ -566,7 +579,7 @@
         if (!TestPackageTransactions(ancestors)) {
             if (fUsingModified) {
                 mapModifiedTx.get<ancestor_score>().erase(modit);
-                failedTx.insert(iter);
+                failedTx.insert(iter->GetTx().GetId());
             }
             continue;
         }
@@ -632,7 +645,7 @@
         vecPriority.pop_back();
 
         // If tx already in block, skip.
-        if (inBlock.count(iter)) {
+        if (inBlock.count(iter->GetTx().GetId())) {
             // Shouldn't happen for priority txs.
             assert(false);
             continue;