diff --git a/pkg/core/transaction/contract_test.go b/pkg/core/transaction/contract_test.go
index 6d6ed4ef0..28bc42032 100644
--- a/pkg/core/transaction/contract_test.go
+++ b/pkg/core/transaction/contract_test.go
@@ -17,7 +17,7 @@ func TestEncodeDecodeContract(t *testing.T) {
 	assert.Equal(t, ContractType, tx.Type)
 	assert.IsType(t, tx.Data, &ContractTX{})
 	assert.Equal(t, 0, int(tx.Version))
-	assert.Equal(t, 1, int(len(tx.Inputs)))
+	assert.Equal(t, 1, len(tx.Inputs))
 
 	input := tx.Inputs[0]
 
diff --git a/pkg/vm/compiler/emit.go b/pkg/vm/compiler/emit.go
index 584979e5d..92be632f8 100644
--- a/pkg/vm/compiler/emit.go
+++ b/pkg/vm/compiler/emit.go
@@ -85,7 +85,7 @@ func emitSyscall(w *bytes.Buffer, api string) error {
 	}
 	buf := make([]byte, len(api)+1)
 	buf[0] = byte(len(api))
-	copy(buf[1:], []byte(api))
+	copy(buf[1:], api)
 	return emit(w, vm.SYSCALL, buf)
 }
 
diff --git a/pkg/vm/emit.go b/pkg/vm/emit.go
index 14556b039..db76fc238 100644
--- a/pkg/vm/emit.go
+++ b/pkg/vm/emit.go
@@ -91,7 +91,7 @@ func EmitSyscall(w *bytes.Buffer, api string) error {
 	}
 	buf := make([]byte, len(api)+1)
 	buf[0] = byte(len(api))
-	copy(buf[1:], []byte(api))
+	copy(buf[1:], api)
 	return Emit(w, SYSCALL, buf)
 }