diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index 574fc9554d..629ae7c0e9 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -2192,11 +2192,11 @@ func MakeChain(ctx *cli.Context, stack *node.Node, readonly bool) (*core.BlockCh
 	vmcfg := vm.Config{EnablePreimageRecording: ctx.Bool(VMEnableDebugFlag.Name)}
 	if ctx.IsSet(VMTraceFlag.Name) {
 		if name := ctx.String(VMTraceFlag.Name); name != "" {
-			var config string
+			var config json.RawMessage
 			if ctx.IsSet(VMTraceConfigFlag.Name) {
-				config = ctx.String(VMTraceConfigFlag.Name)
+				config = json.RawMessage(ctx.String(VMTraceConfigFlag.Name))
 			}
-			t, err := live.Directory.New(name, json.RawMessage(config))
+			t, err := live.Directory.New(name, config)
 			if err != nil {
 				Fatalf("Failed to create tracer %q: %v", name, err)
 			}
diff --git a/core/vm/evm.go b/core/vm/evm.go
index f9e30fbf09..5e30451e0d 100644
--- a/core/vm/evm.go
+++ b/core/vm/evm.go
@@ -188,7 +188,7 @@ func (evm *EVM) Call(caller ContractRef, addr common.Address, input []byte, gas
 	if evm.Config.Tracer != nil {
 		evm.captureBegin(evm.depth, CALL, caller.Address(), addr, input, gas, value.ToBig())
 		defer func(startGas uint64) {
-			evm.captureEnd(evm.depth, CALL, startGas, leftOverGas, ret, err)
+			evm.captureEnd(evm.depth, startGas, leftOverGas, ret, err)
 		}(gas)
 	}
 	// Fail if we're trying to execute above the call depth limit
@@ -260,7 +260,7 @@ func (evm *EVM) CallCode(caller ContractRef, addr common.Address, input []byte,
 	if evm.Config.Tracer != nil {
 		evm.captureBegin(evm.depth, CALLCODE, caller.Address(), addr, input, gas, value.ToBig())
 		defer func(startGas uint64) {
-			evm.captureEnd(evm.depth, CALLCODE, startGas, leftOverGas, ret, err)
+			evm.captureEnd(evm.depth, startGas, leftOverGas, ret, err)
 		}(gas)
 	}
 	// Fail if we're trying to execute above the call depth limit
@@ -315,7 +315,7 @@ func (evm *EVM) DelegateCall(caller ContractRef, addr common.Address, input []by
 		// DELEGATECALL inherits value from parent call
 		evm.captureBegin(evm.depth, DELEGATECALL, caller.Address(), addr, input, gas, parent.value.ToBig())
 		defer func(startGas uint64) {
-			evm.captureEnd(evm.depth, DELEGATECALL, startGas, leftOverGas, ret, err)
+			evm.captureEnd(evm.depth, startGas, leftOverGas, ret, err)
 		}(gas)
 	}
 	// Fail if we're trying to execute above the call depth limit
@@ -356,7 +356,7 @@ func (evm *EVM) StaticCall(caller ContractRef, addr common.Address, input []byte
 	if evm.Config.Tracer != nil {
 		evm.captureBegin(evm.depth, STATICCALL, caller.Address(), addr, input, gas, nil)
 		defer func(startGas uint64) {
-			evm.captureEnd(evm.depth, STATICCALL, startGas, leftOverGas, ret, err)
+			evm.captureEnd(evm.depth, startGas, leftOverGas, ret, err)
 		}(gas)
 	}
 	// Fail if we're trying to execute above the call depth limit
@@ -423,7 +423,7 @@ func (evm *EVM) create(caller ContractRef, codeAndHash *codeAndHash, gas uint64,
 	if evm.Config.Tracer != nil {
 		evm.captureBegin(evm.depth, typ, caller.Address(), address, codeAndHash.code, gas, value.ToBig())
 		defer func(startGas uint64) {
-			evm.captureEnd(evm.depth, typ, startGas, leftOverGas, ret, err)
+			evm.captureEnd(evm.depth, startGas, leftOverGas, ret, err)
 		}(gas)
 	}
 	// Depth check execution. Fail if we're trying to execute above the
@@ -533,7 +533,7 @@ func (evm *EVM) captureBegin(depth int, typ OpCode, from common.Address, to comm
 	}
 }
 
-func (evm *EVM) captureEnd(depth int, typ OpCode, startGas uint64, leftOverGas uint64, ret []byte, err error) {
+func (evm *EVM) captureEnd(depth int, startGas uint64, leftOverGas uint64, ret []byte, err error) {
 	tracer := evm.Config.Tracer
 	if leftOverGas != 0 && tracer.OnGasChange != nil {
 		tracer.OnGasChange(leftOverGas, 0, tracing.GasChangeCallLeftOverReturned)
diff --git a/eth/backend.go b/eth/backend.go
index e1f9650a1f..15e008a07e 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -202,7 +202,11 @@ func New(stack *node.Node, config *ethconfig.Config) (*Ethereum, error) {
 		}
 	)
 	if config.VMTrace != "" {
-		t, err := live.Directory.New(config.VMTrace, json.RawMessage(config.VMTraceConfig))
+		var traceConfig json.RawMessage
+		if config.VMTraceConfig != "" {
+			traceConfig = json.RawMessage(config.VMTraceConfig)
+		}
+		t, err := live.Directory.New(config.VMTrace, traceConfig)
 		if err != nil {
 			return nil, fmt.Errorf("Failed to create tracer %s: %v", config.VMTrace, err)
 		}