diff --git a/libraries/chain/include/golos/chain/steem_object_types.hpp b/libraries/chain/include/golos/chain/steem_object_types.hpp
index 69cd50c4b0..9e7aa6a0f4 100644
--- a/libraries/chain/include/golos/chain/steem_object_types.hpp
+++ b/libraries/chain/include/golos/chain/steem_object_types.hpp
@@ -172,7 +172,7 @@ namespace fc {
         }
 
         template<typename Stream, typename T>
-        inline void unpack(Stream &s, chainbase::object_id<T> &id) {
+        inline void unpack(Stream &s, chainbase::object_id<T> &id, uint32_t = 0) {
             s.read((char *)&id._id, sizeof(id._id));
         }
     }
@@ -189,16 +189,16 @@ namespace fc {
         }
 
         template<typename T>
-        inline void unpack(const golos::chain::buffer_type &raw, T &v) {
+        inline void unpack(const golos::chain::buffer_type &raw, T &v, uint32_t depth = 0) {
             datastream<const char *> ds(raw.data(), raw.size());
-            unpack(ds, v);
+            unpack(ds, v, depth);
         }
 
         template<typename T>
-        inline T unpack(const golos::chain::buffer_type &raw) {
+        inline T unpack(const golos::chain::buffer_type &raw, uint32_t depth = 0) {
             T v;
             datastream<const char *> ds(raw.data(), raw.size());
-            unpack(ds, v);
+            unpack(ds, v, depth);
             return v;
         }
     }
diff --git a/tests/tests/serialization_tests.cpp b/tests/tests/serialization_tests.cpp
index c76404f7f4..545d55c44c 100644
--- a/tests/tests/serialization_tests.cpp
+++ b/tests/tests/serialization_tests.cpp
@@ -314,5 +314,97 @@ BOOST_FIXTURE_TEST_SUITE(serialization_tests, clean_database_fixture)
         FC_LOG_AND_RETHROW();
     }
 
+BOOST_AUTO_TEST_CASE(unpack_clear_test) { try {
+    std::stringstream ss1;
+    std::stringstream ss2;
+
+    signed_block b1;
+
+    for (int i = 0; i < 10; i++) {
+        signed_transaction tx;
+
+        vote_operation op;
+        op.voter = "alice";
+        op.author = "bob";
+        op.permlink = "permlink1";
+        op.weight = STEEMIT_100_PERCENT;
+        tx.operations.push_back(op);
+
+        vote_operation op2;
+        op2.voter = "charlie";
+        op2.author = "sam";
+        op2.permlink = "permlink2";
+        op2.weight = STEEMIT_100_PERCENT;
+        tx.operations.push_back(op2);
+
+        tx.ref_block_num = 1000;
+        tx.ref_block_prefix = 1000000000;
+        tx.expiration = fc::time_point_sec(1514764800 + i);
+
+        b1.transactions.push_back(tx);
+    }
+
+    signed_block b2;
+
+    for (int i = 0; i < 20; i++) {
+        signed_transaction tx;
+        vote_operation op;
+        op.voter = "dave";
+        op.author = "greg";
+        op.permlink = "foobar";
+        op.weight = STEEMIT_100_PERCENT/2;
+        tx.ref_block_num = 4000;
+        tx.ref_block_prefix = 4000000000;
+        tx.expiration = fc::time_point_sec(1714764800 + i);
+        tx.operations.push_back(op);
+
+        b2.transactions.push_back(tx);
+    }
+
+    fc::raw::pack(ss2, b2);
+    fc::raw::pack(ss1, b1);
+
+    signed_block unpacked_block;
+    fc::raw::unpack(ss2, unpacked_block);
+
+    // This operation should completely overwrite signed block 'b2'
+    fc::raw::unpack(ss1, unpacked_block);
+
+    BOOST_REQUIRE(b1.transactions.size() == unpacked_block.transactions.size());
+    for (size_t i = 0; i < unpacked_block.transactions.size(); i++) {
+        signed_transaction tx = unpacked_block.transactions[i];
+        BOOST_REQUIRE(unpacked_block.transactions[i].operations.size() == b1.transactions[i].operations.size());
+
+        vote_operation op = tx.operations[0].get<vote_operation>();
+        BOOST_REQUIRE(op.voter == "alice");
+        BOOST_REQUIRE(op.author == "bob");
+        BOOST_REQUIRE(op.permlink == "permlink1");
+        BOOST_REQUIRE(op.weight == STEEMIT_100_PERCENT);
+
+        vote_operation op2 = tx.operations[1].get<vote_operation>();
+        BOOST_REQUIRE(op2.voter == "charlie");
+        BOOST_REQUIRE(op2.author == "sam");
+        BOOST_REQUIRE(op2.permlink == "permlink2");
+        BOOST_REQUIRE(op2.weight == STEEMIT_100_PERCENT);
+
+        BOOST_REQUIRE(tx.ref_block_num == 1000);
+        BOOST_REQUIRE(tx.ref_block_prefix == 1000000000);
+        BOOST_REQUIRE(tx.expiration == fc::time_point_sec(1514764800 + i));
+    }
+} FC_LOG_AND_RETHROW(); }
+
+BOOST_AUTO_TEST_CASE(unpack_recursion_test) { try {
+    std::stringstream ss;
+    int recursion_level = 100000;
+    uint64_t allocation_per_level = 500000;
+    for (int i = 0; i < recursion_level; i++) {
+        fc::raw::pack(ss, unsigned_int(allocation_per_level));
+        fc::raw::pack(ss, static_cast<uint8_t>(variant::array_type));
+    }
+    std::vector<fc::variant> v;
+    STEEMIT_REQUIRE_THROW(fc::raw::unpack(ss, v), fc::assert_exception);
+} FC_LOG_AND_RETHROW(); }
+
+
 BOOST_AUTO_TEST_SUITE_END()
 #endif
diff --git a/thirdparty/fc b/thirdparty/fc
index afa113d86e..ca64acb909 160000
--- a/thirdparty/fc
+++ b/thirdparty/fc
@@ -1 +1 @@
-Subproject commit afa113d86e1e7ba91c62e9fe256de921f375b608
+Subproject commit ca64acb909f6c9fabdca1b07e0729eb2181e5eaf