diff --git a/src/avalanche/proof.h b/src/avalanche/proof.h
--- a/src/avalanche/proof.h
+++ b/src/avalanche/proof.h
@@ -39,8 +39,9 @@
 
 public:
     explicit Stake() = default;
-    Stake(COutPoint utxo_, Amount amount_, uint32_t height_, CPubKey pubkey_)
-        : utxo(utxo_), amount(amount_), height(height_),
+    Stake(COutPoint utxo_, Amount amount_, uint32_t height_, bool is_coinbase,
+          CPubKey pubkey_)
+        : utxo(utxo_), amount(amount_), height(height_ << 1 | is_coinbase),
           pubkey(std::move(pubkey_)) {}
 
     ADD_SERIALIZE_METHODS;
diff --git a/src/avalanche/proofbuilder.h b/src/avalanche/proofbuilder.h
--- a/src/avalanche/proofbuilder.h
+++ b/src/avalanche/proofbuilder.h
@@ -34,7 +34,8 @@
         : sequence(sequence_), expirationTime(expirationTime_),
           master(std::move(master_)) {}
 
-    bool addUTXO(COutPoint utxo, Amount amount, uint32_t height, CKey key);
+    bool addUTXO(COutPoint utxo, Amount amount, uint32_t height,
+                 bool is_coinbase, CKey key);
 
     Proof build();
 
diff --git a/src/avalanche/proofbuilder.cpp b/src/avalanche/proofbuilder.cpp
--- a/src/avalanche/proofbuilder.cpp
+++ b/src/avalanche/proofbuilder.cpp
@@ -25,13 +25,14 @@
 }
 
 bool ProofBuilder::addUTXO(COutPoint utxo, Amount amount, uint32_t height,
-                           CKey key) {
+                           bool is_coinbase, CKey key) {
     if (!key.IsValid()) {
         return false;
     }
 
-    stakes.emplace_back(Stake(std::move(utxo), amount, height, key.GetPubKey()),
-                        std::move(key));
+    stakes.emplace_back(
+        Stake(std::move(utxo), amount, height, is_coinbase, key.GetPubKey()),
+        std::move(key));
     return true;
 }
 
@@ -70,7 +71,7 @@
 
     ProofBuilder pb(0, std::numeric_limits<uint32_t>::max(), CPubKey());
     pb.addUTXO(COutPoint(TxId(GetRandHash()), 0), (int64_t(score) * COIN) / 100,
-               0, std::move(key));
+               0, false, std::move(key));
     return pb.build();
 }
 
diff --git a/src/avalanche/test/proof_tests.cpp b/src/avalanche/test/proof_tests.cpp
--- a/src/avalanche/test/proof_tests.cpp
+++ b/src/avalanche/test/proof_tests.cpp
@@ -46,7 +46,7 @@
         key.MakeNewKey(true);
         pb.addUTXO(COutPoint(TxId(GetRandHash()), InsecureRand32()),
                    int64_t(InsecureRand32()) * COIN / 100, InsecureRand32(),
-                   key);
+                   InsecureRandBool(), key);
     }
 
     Proof p = pb.build();
diff --git a/src/avalanche/test/util.cpp b/src/avalanche/test/util.cpp
--- a/src/avalanche/test/util.cpp
+++ b/src/avalanche/test/util.cpp
@@ -19,7 +19,7 @@
 
     ProofBuilder pb(0, std::numeric_limits<uint32_t>::max(), CPubKey());
     pb.addUTXO(COutPoint(TxId(GetRandHash()), 0), (int64_t(score) * COIN) / 100,
-               0, std::move(key));
+               0, false, std::move(key));
     return pb.build();
 }
 
diff --git a/src/rpc/avalanche.cpp b/src/rpc/avalanche.cpp
--- a/src/rpc/avalanche.cpp
+++ b/src/rpc/avalanche.cpp
@@ -183,7 +183,7 @@
             iscbparam.isNull() ? false : iscbparam.get_bool();
         CKey key = DecodeSecret(find_value(stake, "privatekey").get_str());
 
-        if (!pb.addUTXO(utxo, amount, uint32_t(height) << 1 | iscoinbase,
+        if (!pb.addUTXO(utxo, amount, uint32_t(height), iscoinbase,
                         std::move(key))) {
             throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid private key");
         }