diff --git a/accounts/abi/bind/backends/simulated_test.go b/accounts/abi/bind/backends/simulated_test.go
index a41d168411..65a3d72bd7 100644
--- a/accounts/abi/bind/backends/simulated_test.go
+++ b/accounts/abi/bind/backends/simulated_test.go
@@ -424,10 +424,12 @@ func TestEstimateGas(t *testing.T) {
 			function OOG() public { for (uint i = 0; ; i++) {}}
 			function Assert() public { assert(false);}
 			function Valid() public {}
+			function Difficulty() public { assert(block.difficulty == 0); }
 		}
 	*/
-	const contractAbi = "[{\"inputs\":[],\"name\":\"Assert\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"OOG\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"PureRevert\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"Revert\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"Valid\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"}]"
-	const contractBin = "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"
+
+	const contractAbi = "[{\"inputs\":[],\"name\":\"Assert\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"Difficulty\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"OOG\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"PureRevert\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"Revert\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"Valid\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"}]"
+	const contractBin = "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"
 
 	key, _ := crypto.GenerateKey()
 	addr := crypto.PubkeyToAddress(key.PublicKey)
@@ -508,7 +510,15 @@ func TestEstimateGas(t *testing.T) {
 			GasPrice: big.NewInt(0),
 			Value:    nil,
 			Data:     common.Hex2Bytes("e09fface"),
-		}, 21275, nil, nil},
+		}, 21296, nil, nil},
+		{"Difficulty", ethereum.CallMsg{
+			From:     addr,
+			To:       &contractAddr,
+			Gas:      100000,
+			GasPrice: big.NewInt(0),
+			Value:    nil,
+			Data:     common.Hex2Bytes("91b4a0e7"),
+		}, 21230, nil, nil},
 	}
 	for _, c := range cases {
 		got, err := sim.EstimateGas(context.Background(), c.message)
diff --git a/core/vm/instructions.go b/core/vm/instructions.go
index 2e1a5f7c3d..35c23031bd 100644
--- a/core/vm/instructions.go
+++ b/core/vm/instructions.go
@@ -489,7 +489,7 @@ func opNumber(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]b
 }
 
 func opDifficulty(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
-	v, _ := uint256.FromBig(interpreter.evm.Context.Difficulty)
+	v := uint256.NewInt(0)
 	scope.Stack.push(v)
 	return nil, nil
 }
diff --git a/core/vm/runtime/runtime_test.go b/core/vm/runtime/runtime_test.go
index 796d3b4434..274f4d7c4a 100644
--- a/core/vm/runtime/runtime_test.go
+++ b/core/vm/runtime/runtime_test.go
@@ -83,6 +83,26 @@ func TestEVM(t *testing.T) {
 	}, nil, nil)
 }
 
+func TestDifficulty(t *testing.T) {
+	ret, _, err := Execute([]byte{
+		byte(vm.DIFFICULTY),
+		byte(vm.PUSH1), 0,
+		byte(vm.MSTORE),
+		byte(vm.PUSH1), 32,
+		byte(vm.PUSH1), 0,
+		byte(vm.RETURN),
+	}, nil, &Config{Difficulty: big.NewInt(1)})
+
+	if err != nil {
+		t.Fatal("didn't expect error", err)
+	}
+
+	num := new(big.Int).SetBytes(ret)
+	if num.Cmp(big.NewInt(0)) != 0 {
+		t.Error("Expected 0, got", num)
+	}
+}
+
 func TestExecute(t *testing.T) {
 	ret, _, err := Execute([]byte{
 		byte(vm.PUSH1), 10,