diff --git a/cli/nep11_test.go b/cli/nep11_test.go
index a1d967cc9..519f152ce 100644
--- a/cli/nep11_test.go
+++ b/cli/nep11_test.go
@@ -312,7 +312,7 @@ func TestNEP11_OwnerOf_BalanceOf_Transfer(t *testing.T) {
 		ScriptHash: verifyH,
 		Name:       "OnNEP11Payment",
 		Item: stackitem.NewArray([]stackitem.Item{
-			stackitem.NewByteArray(nftOwnerHash.BytesBE()),
+			stackitem.NewBuffer(nftOwnerHash.BytesBE()),
 			stackitem.NewBigInteger(big.NewInt(1)),
 			stackitem.NewByteArray(tokenID1),
 			stackitem.NewByteArray([]byte("some_data")),
diff --git a/pkg/smartcontract/manifest/manifest.go b/pkg/smartcontract/manifest/manifest.go
index 2efed7b23..8fde178dc 100644
--- a/pkg/smartcontract/manifest/manifest.go
+++ b/pkg/smartcontract/manifest/manifest.go
@@ -1,12 +1,14 @@
 package manifest
 
 import (
+	"bytes"
 	"encoding/json"
 	"errors"
 	"math"
 
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
+	ojson "github.com/virtuald/go-ordered-json"
 )
 
 const (
@@ -140,10 +142,7 @@ func (m *Manifest) ToStackItem() (stackitem.Item, error) {
 		}
 		trusts = stackitem.Make(tItems)
 	}
-	extra := stackitem.Make("null")
-	if m.Extra != nil {
-		extra = stackitem.NewByteArray(m.Extra)
-	}
+	extra := extraToStackItem(m.Extra)
 	return stackitem.NewStruct([]stackitem.Item{
 		stackitem.Make(m.Name),
 		stackitem.Make(groups),
@@ -156,6 +155,29 @@ func (m *Manifest) ToStackItem() (stackitem.Item, error) {
 	}), nil
 }
 
+// extraToStackItem removes indentation from `Extra` field in JSON and
+// converts it to a byte-array stack item.
+func extraToStackItem(rawExtra []byte) stackitem.Item {
+	extra := stackitem.Make("null")
+	if rawExtra == nil || string(rawExtra) == "null" {
+		return extra
+	}
+
+	d := ojson.NewDecoder(bytes.NewReader(rawExtra))
+	// The result is put directly in the database and affects state-root calculation,
+	// thus use ordered map to stay compatible with C# implementation.
+	d.UseOrderedObject()
+	// Prevent accidental precision loss.
+	d.UseNumber()
+
+	var obj interface{}
+
+	// The error can't really occur because `json.RawMessage` is already a valid json.
+	_ = d.Decode(&obj)
+	res, _ := ojson.Marshal(obj)
+	return stackitem.NewByteArray(res)
+}
+
 // FromStackItem converts stackitem.Item to Manifest.
 func (m *Manifest) FromStackItem(item stackitem.Item) error {
 	var err error
diff --git a/pkg/smartcontract/manifest/manifest_test.go b/pkg/smartcontract/manifest/manifest_test.go
index 844ec16ab..1af90a05f 100644
--- a/pkg/smartcontract/manifest/manifest_test.go
+++ b/pkg/smartcontract/manifest/manifest_test.go
@@ -289,7 +289,7 @@ func TestManifestToStackItem(t *testing.T) {
 					},
 				},
 			},
-			Extra: []byte(`even not a json allowed`),
+			Extra: []byte(`"even string allowed"`),
 		}
 		check(t, expected)
 	})
@@ -395,3 +395,25 @@ func TestABI_FromStackItemErrors(t *testing.T) {
 		})
 	}
 }
+
+func TestExtraToStackItem(t *testing.T) {
+	testCases := []struct {
+		raw, expected string
+	}{
+		{"null", "null"},
+		{"1", "1"},
+		{"1.23456789101112131415", "1.23456789101112131415"},
+		{`"string with space"`, `"string with space"`},
+		{`{ "a":1, "sss" : {"m" : 1, "a" : 2} , "x"  :  2  ,"c" :3,"z":4,  "s":"5"}`,
+			`{"a":1,"sss":{"m":1,"a":2},"x":2,"c":3,"z":4,"s":"5"}`},
+		{`  [ 1, "array", { "d": "z", "a":"x",  "c" : "y",  "b":3}]`,
+			`[1,"array",{"d":"z","a":"x","c":"y","b":3}]`},
+	}
+
+	for _, tc := range testCases {
+		res := extraToStackItem([]byte(tc.raw))
+		actual, ok := res.Value().([]byte)
+		require.True(t, ok)
+		require.Equal(t, tc.expected, string(actual))
+	}
+}
diff --git a/pkg/vm/stackitem/serialization.go b/pkg/vm/stackitem/serialization.go
index 3a40f4590..b30cb02c1 100644
--- a/pkg/vm/stackitem/serialization.go
+++ b/pkg/vm/stackitem/serialization.go
@@ -129,7 +129,10 @@ func decodeBinaryStackItem(r *io.BinReader, allowInvalid bool) Item {
 	switch t {
 	case ByteArrayT, BufferT:
 		data := r.ReadVarBytes(MaxSize)
-		return NewByteArray(data)
+		if t == ByteArrayT {
+			return NewByteArray(data)
+		}
+		return NewBuffer(data)
 	case BooleanT:
 		var b = r.ReadBool()
 		return NewBool(b)