diff --git a/src/MiningCore/Blockchain/Bitcoin/BitcoinJob.cs b/src/MiningCore/Blockchain/Bitcoin/BitcoinJob.cs
index 86bf51285..ce28737aa 100644
--- a/src/MiningCore/Blockchain/Bitcoin/BitcoinJob.cs
+++ b/src/MiningCore/Blockchain/Bitcoin/BitcoinJob.cs
@@ -116,94 +116,120 @@ protected virtual void BuildMerkleBranches()
                 .ToArray();
         }
 
-        protected virtual void BuildCoinbase()
-        {
-            // generate script parts
-            var sigScriptInitial = GenerateScriptSigInitial();
-            var sigScriptInitialBytes = sigScriptInitial.ToBytes();
-
-            var sigScriptLength = (uint) (
-                sigScriptInitial.Length +
-                extraNoncePlaceHolderLength +
-                scriptSigFinalBytes.Length);
-
-            // output transaction
-            txOut = CreateOutputTransaction();
-
-            // build coinbase initial
-            using (var stream = new MemoryStream())
-            {
-                var bs = new BitcoinStream(stream, true);
-
-                // version
-                bs.ReadWrite(ref txVersion);
-
-                // timestamp for POS coins
-                if (isPoS)
-                {
-                    var timestamp = BlockTemplate.CurTime;
-                    bs.ReadWrite(ref timestamp);
-                }
-
-                // serialize (simulated) input transaction
-                bs.ReadWriteAsVarInt(ref txInputCount);
-                bs.ReadWrite(ref sha256Empty);
-                bs.ReadWrite(ref txInPrevOutIndex);
-
-                // signature script initial part
-                bs.ReadWriteAsVarInt(ref sigScriptLength);
-                bs.ReadWrite(ref sigScriptInitialBytes);
-
-                // done	
-                coinbaseInitial = stream.ToArray();
-                coinbaseInitialHex = coinbaseInitial.ToHexString();
-            }
-
-            // build coinbase final
-            using (var stream = new MemoryStream())
-            {
-                var bs = new BitcoinStream(stream, true);
-
-                // signature script final part
-                bs.ReadWrite(ref scriptSigFinalBytes);
-
-                // tx in sequence
-                bs.ReadWrite(ref txInSequence);
-
-                // serialize output transaction
-                var txOutBytes = SerializeOutputTransaction(txOut);
-                bs.ReadWrite(ref txOutBytes);
-
-                // misc
-                bs.ReadWrite(ref txLockTime);
-
-                // done
-                coinbaseFinal = stream.ToArray();
-                coinbaseFinalHex = coinbaseFinal.ToHexString();
-            }
-        }
-
-        protected virtual byte[] SerializeOutputTransaction(Transaction tx)
-        {
-            using (var stream = new MemoryStream())
-            {
-                var bs = new BitcoinStream(stream, true);
-
-                // serialize outputs
-                var vout = tx.Outputs;
-                bs.ReadWrite<TxOutList, TxOut>(ref vout);
-
-                // serialize witness (segwit)
-                if (!string.IsNullOrEmpty(BlockTemplate.DefaultWitnessCommitment))
-                {
-                    var witScript = new WitScript(BlockTemplate.DefaultWitnessCommitment);
-                    var raw = witScript.ToBytes();
-                    bs.ReadWrite(ref raw);
-                }
-
-                return stream.ToArray();
-            }
-        }
+        protected virtual void BuildCoinbase()
+        {
+            // generate script parts
+            var sigScriptInitial = GenerateScriptSigInitial();
+            var sigScriptInitialBytes = sigScriptInitial.ToBytes();
+
+            var sigScriptLength = (uint) (
+                sigScriptInitial.Length +
+                extraNoncePlaceHolderLength +
+                scriptSigFinalBytes.Length);
+
+            // output transaction
+            txOut = CreateOutputTransaction();
+
+            // build coinbase initial
+            using (var stream = new MemoryStream())
+            {
+                var bs = new BitcoinStream(stream, true);
+
+                // version
+                bs.ReadWrite(ref txVersion);
+
+                // timestamp for POS coins
+                if (isPoS)
+                {
+                    var timestamp = BlockTemplate.CurTime;
+                    bs.ReadWrite(ref timestamp);
+                }
+
+                // serialize (simulated) input transaction
+                bs.ReadWriteAsVarInt(ref txInputCount);
+                bs.ReadWrite(ref sha256Empty);
+                bs.ReadWrite(ref txInPrevOutIndex);
+
+                // signature script initial part
+                bs.ReadWriteAsVarInt(ref sigScriptLength);
+                bs.ReadWrite(ref sigScriptInitialBytes);
+
+                // done	
+                coinbaseInitial = stream.ToArray();
+                coinbaseInitialHex = coinbaseInitial.ToHexString();
+            }
+
+            // build coinbase final
+            using (var stream = new MemoryStream())
+            {
+                var bs = new BitcoinStream(stream, true);
+
+                // signature script final part
+                bs.ReadWrite(ref scriptSigFinalBytes);
+
+                // tx in sequence
+                bs.ReadWrite(ref txInSequence);
+
+                // serialize output transaction
+                var txOutBytes = SerializeOutputTransaction(txOut);
+                bs.ReadWrite(ref txOutBytes);
+
+                // misc
+                bs.ReadWrite(ref txLockTime);
+
+                // done
+                coinbaseFinal = stream.ToArray();
+                coinbaseFinalHex = coinbaseFinal.ToHexString();
+            }
+        }
+
+        protected virtual byte[] SerializeOutputTransaction(Transaction tx)
+        {
+            var withDefaultWitnessCommitment = !string.IsNullOrEmpty(BlockTemplate.DefaultWitnessCommitment);
+
+            var outputCount = (uint)tx.Outputs.Count;
+            if (withDefaultWitnessCommitment)
+                outputCount++;
+
+            using (var stream = new MemoryStream())
+            {
+                var bs = new BitcoinStream(stream, true);
+
+                // write output count
+                bs.ReadWriteAsVarInt(ref outputCount);
+
+                long amount;
+                byte[] raw;
+                uint rawLength;
+
+                // serialize witness (segwit)
+                if (withDefaultWitnessCommitment)
+                {
+                    amount = 0;
+                    raw = BlockTemplate.DefaultWitnessCommitment.HexToByteArray();
+                    rawLength = (uint)raw.Length;
+
+                    bs.ReadWrite(ref amount);
+                    bs.ReadWriteAsVarInt(ref rawLength);
+                    bs.ReadWrite(ref raw);
+                }
+
+                // serialize outputs
+                foreach (var output in tx.Outputs)
+                {
+                    amount = output.Value.Satoshi;
+                    var outScript = output.ScriptPubKey;
+                    raw = outScript.ToBytes(true);
+                    rawLength = (uint)raw.Length;
+
+                    bs.ReadWrite(ref amount);
+                    bs.ReadWriteAsVarInt(ref rawLength);
+                    bs.ReadWrite(ref raw);
+                }
+
+                return stream.ToArray();
+            }
+        }
 
         protected virtual Script GenerateScriptSigInitial()
         {