diff --git a/core/blockchain_test.go b/core/blockchain_test.go
index 700a30a16f..cb1df8d4b0 100644
--- a/core/blockchain_test.go
+++ b/core/blockchain_test.go
@@ -928,7 +928,7 @@ func TestReorgSideEvent(t *testing.T) {
 	replacementBlocks, _ := GenerateChain(gspec.Config, genesis, db, 4, func(i int, gen *BlockGen) {
 		tx, err := types.SignTx(types.NewContractCreation(gen.TxNonce(addr1), new(big.Int), big.NewInt(1000000), new(big.Int), nil), signer, key1)
 		if i == 2 {
-			gen.OffsetTime(-1)
+			gen.OffsetTime(-9)
 		}
 		if err != nil {
 			t.Fatalf("failed to create tx: %v", err)
diff --git a/core/dao_test.go b/core/dao_test.go
index d6e11d78ae..b9898ff7c8 100644
--- a/core/dao_test.go
+++ b/core/dao_test.go
@@ -40,14 +40,22 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 	// Create the concurrent, conflicting two nodes
 	proDb, _ := ethdb.NewMemDatabase()
 	gspec.MustCommit(proDb)
-	proConf := &params.ChainConfig{HomesteadBlock: big.NewInt(0), DAOForkBlock: forkBlock, DAOForkSupport: true}
-	proBc, _ := NewBlockChain(proDb, proConf, ethash.NewFaker(), vm.Config{})
+
+	proConf := *params.TestChainConfig
+	proConf.DAOForkBlock = forkBlock
+	proConf.DAOForkSupport = true
+
+	proBc, _ := NewBlockChain(proDb, &proConf, ethash.NewFaker(), vm.Config{})
 	defer proBc.Stop()
 
 	conDb, _ := ethdb.NewMemDatabase()
 	gspec.MustCommit(conDb)
-	conConf := &params.ChainConfig{HomesteadBlock: big.NewInt(0), DAOForkBlock: forkBlock, DAOForkSupport: false}
-	conBc, _ := NewBlockChain(conDb, conConf, ethash.NewFaker(), vm.Config{})
+
+	conConf := *params.TestChainConfig
+	conConf.DAOForkBlock = forkBlock
+	conConf.DAOForkSupport = false
+
+	conBc, _ := NewBlockChain(conDb, &conConf, ethash.NewFaker(), vm.Config{})
 	defer conBc.Stop()
 
 	if _, err := proBc.InsertChain(prefix); err != nil {
@@ -61,7 +69,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 		// Create a pro-fork block, and try to feed into the no-fork chain
 		db, _ = ethdb.NewMemDatabase()
 		gspec.MustCommit(db)
-		bc, _ := NewBlockChain(db, conConf, ethash.NewFaker(), vm.Config{})
+		bc, _ := NewBlockChain(db, &conConf, ethash.NewFaker(), vm.Config{})
 		defer bc.Stop()
 
 		blocks := conBc.GetBlocksFromHash(conBc.CurrentBlock().Hash(), int(conBc.CurrentBlock().NumberU64()))
@@ -71,19 +79,19 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 		if _, err := bc.InsertChain(blocks); err != nil {
 			t.Fatalf("failed to import contra-fork chain for expansion: %v", err)
 		}
-		blocks, _ = GenerateChain(proConf, conBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
+		blocks, _ = GenerateChain(&proConf, conBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
 		if _, err := conBc.InsertChain(blocks); err == nil {
 			t.Fatalf("contra-fork chain accepted pro-fork block: %v", blocks[0])
 		}
 		// Create a proper no-fork block for the contra-forker
-		blocks, _ = GenerateChain(conConf, conBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
+		blocks, _ = GenerateChain(&conConf, conBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
 		if _, err := conBc.InsertChain(blocks); err != nil {
 			t.Fatalf("contra-fork chain didn't accepted no-fork block: %v", err)
 		}
 		// Create a no-fork block, and try to feed into the pro-fork chain
 		db, _ = ethdb.NewMemDatabase()
 		gspec.MustCommit(db)
-		bc, _ = NewBlockChain(db, proConf, ethash.NewFaker(), vm.Config{})
+		bc, _ = NewBlockChain(db, &proConf, ethash.NewFaker(), vm.Config{})
 		defer bc.Stop()
 
 		blocks = proBc.GetBlocksFromHash(proBc.CurrentBlock().Hash(), int(proBc.CurrentBlock().NumberU64()))
@@ -93,12 +101,12 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 		if _, err := bc.InsertChain(blocks); err != nil {
 			t.Fatalf("failed to import pro-fork chain for expansion: %v", err)
 		}
-		blocks, _ = GenerateChain(conConf, proBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
+		blocks, _ = GenerateChain(&conConf, proBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
 		if _, err := proBc.InsertChain(blocks); err == nil {
 			t.Fatalf("pro-fork chain accepted contra-fork block: %v", blocks[0])
 		}
 		// Create a proper pro-fork block for the pro-forker
-		blocks, _ = GenerateChain(proConf, proBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
+		blocks, _ = GenerateChain(&proConf, proBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
 		if _, err := proBc.InsertChain(blocks); err != nil {
 			t.Fatalf("pro-fork chain didn't accepted pro-fork block: %v", err)
 		}
@@ -106,7 +114,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 	// Verify that contra-forkers accept pro-fork extra-datas after forking finishes
 	db, _ = ethdb.NewMemDatabase()
 	gspec.MustCommit(db)
-	bc, _ := NewBlockChain(db, conConf, ethash.NewFaker(), vm.Config{})
+	bc, _ := NewBlockChain(db, &conConf, ethash.NewFaker(), vm.Config{})
 	defer bc.Stop()
 
 	blocks := conBc.GetBlocksFromHash(conBc.CurrentBlock().Hash(), int(conBc.CurrentBlock().NumberU64()))
@@ -116,14 +124,14 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 	if _, err := bc.InsertChain(blocks); err != nil {
 		t.Fatalf("failed to import contra-fork chain for expansion: %v", err)
 	}
-	blocks, _ = GenerateChain(proConf, conBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
+	blocks, _ = GenerateChain(&proConf, conBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
 	if _, err := conBc.InsertChain(blocks); err != nil {
 		t.Fatalf("contra-fork chain didn't accept pro-fork block post-fork: %v", err)
 	}
 	// Verify that pro-forkers accept contra-fork extra-datas after forking finishes
 	db, _ = ethdb.NewMemDatabase()
 	gspec.MustCommit(db)
-	bc, _ = NewBlockChain(db, proConf, ethash.NewFaker(), vm.Config{})
+	bc, _ = NewBlockChain(db, &proConf, ethash.NewFaker(), vm.Config{})
 	defer bc.Stop()
 
 	blocks = proBc.GetBlocksFromHash(proBc.CurrentBlock().Hash(), int(proBc.CurrentBlock().NumberU64()))
@@ -133,7 +141,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 	if _, err := bc.InsertChain(blocks); err != nil {
 		t.Fatalf("failed to import pro-fork chain for expansion: %v", err)
 	}
-	blocks, _ = GenerateChain(conConf, proBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
+	blocks, _ = GenerateChain(&conConf, proBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
 	if _, err := proBc.InsertChain(blocks); err != nil {
 		t.Fatalf("pro-fork chain didn't accept contra-fork block post-fork: %v", err)
 	}
diff --git a/params/config.go b/params/config.go
index 324620ad5c..5c6f0b6bf7 100644
--- a/params/config.go
+++ b/params/config.go
@@ -55,7 +55,7 @@ var (
 		EIP150Hash:     common.HexToHash("0x41941023680923e0fe4d74a34bdac8141f2540e3ae90623718e47d66d1ca4a2d"),
 		EIP155Block:    big.NewInt(10),
 		EIP158Block:    big.NewInt(10),
-		ByzantiumBlock: big.NewInt(math.MaxInt64), // Don't enable yet
+		ByzantiumBlock: big.NewInt(1700000),
 
 		Ethash: new(EthashConfig),
 	}
@@ -86,8 +86,8 @@ var (
 	// means that all fields must be set at all times. This forces
 	// anyone adding flags to the config to also have to set these
 	// fields.
-	AllProtocolChanges = &ChainConfig{big.NewInt(1337), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(math.MaxInt64) /*disabled*/, new(EthashConfig), nil}
-	TestChainConfig    = &ChainConfig{big.NewInt(1), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), nil, new(EthashConfig), nil}
+	AllProtocolChanges = &ChainConfig{big.NewInt(1337), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), new(EthashConfig), nil}
+	TestChainConfig    = &ChainConfig{big.NewInt(1), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), new(EthashConfig), nil}
 	TestRules          = TestChainConfig.Rules(new(big.Int))
 )