diff --git a/go.sum b/go.sum
index 375d84169..c2cbaae96 100644
--- a/go.sum
+++ b/go.sum
@@ -97,8 +97,8 @@ github.com/nspcc-dev/dbft v0.0.0-20191209120240-0d6b7568d9ae h1:T5V1QANlNMKun0EP
 github.com/nspcc-dev/dbft v0.0.0-20191209120240-0d6b7568d9ae/go.mod h1:3FjXOoHmA51EGfb5GS/HOv7VdmngNRTssSeQ729dvGY=
 github.com/nspcc-dev/dbft v0.0.0-20200117124306-478e5cfbf03a h1:ajvxgEe9qY4vvoSmrADqdDx7hReodKTnT2IXN++qZG8=
 github.com/nspcc-dev/dbft v0.0.0-20200117124306-478e5cfbf03a/go.mod h1:/YFK+XOxxg0Bfm6P92lY5eDSLYfp06XOdL8KAVgXjVk=
-github.com/nspcc-dev/dbft v0.0.0-20200130105505-02c208d154bf h1:7QLeZnBQZ8eJeYksP7tnENG2ZEOZhHTJBC6LkFt4Ok8=
-github.com/nspcc-dev/dbft v0.0.0-20200130105505-02c208d154bf/go.mod h1:O0qtn62prQSqizzoagHmuuKoz8QMkU3SzBoKdEvm3aQ=
+github.com/nspcc-dev/dbft v0.0.0-20200203121303-549ecf2daaa1 h1:feHDSBix9oAVt5QzGABQczZo7dNWyeDKClLGwKvSJ/w=
+github.com/nspcc-dev/dbft v0.0.0-20200203121303-549ecf2daaa1/go.mod h1:O0qtn62prQSqizzoagHmuuKoz8QMkU3SzBoKdEvm3aQ=
 github.com/nspcc-dev/neofs-crypto v0.2.0 h1:ftN+59WqxSWz/RCgXYOfhmltOOqU+udsNQSvN6wkFck=
 github.com/nspcc-dev/neofs-crypto v0.2.0/go.mod h1:F/96fUzPM3wR+UGsPi3faVNmFlA9KAEAUQR7dMxZmNA=
 github.com/nspcc-dev/neofs-crypto v0.2.3 h1:aca3X2aly92ENRbFK+kH6Hd+J9EQ4Eu6XMVoITSIKtc=
diff --git a/pkg/compiler/codegen.go b/pkg/compiler/codegen.go
index 1da9dcd78..8836cc342 100644
--- a/pkg/compiler/codegen.go
+++ b/pkg/compiler/codegen.go
@@ -540,17 +540,7 @@ func (c *codegen) Visit(node ast.Node) ast.Visitor {
 		}
 		// Do not swap for builtin functions.
 		if !isBuiltin {
-			if numArgs == 2 {
-				emit.Opcode(c.prog.BinWriter, opcode.SWAP)
-			} else if numArgs == 3 {
-				emit.Int(c.prog.BinWriter, 2)
-				emit.Opcode(c.prog.BinWriter, opcode.XSWAP)
-			} else {
-				for i := 1; i < numArgs; i++ {
-					emit.Int(c.prog.BinWriter, int64(i))
-					emit.Opcode(c.prog.BinWriter, opcode.ROLL)
-				}
-			}
+			c.emitReverse(numArgs)
 		}
 
 		// Check builtin first to avoid nil pointer on funcScope!
@@ -680,6 +670,22 @@ func (c *codegen) Visit(node ast.Node) ast.Visitor {
 	return c
 }
 
+// emitReverse reverses top num items of the stack.
+func (c *codegen) emitReverse(num int) {
+	switch num {
+	case 2:
+		emit.Opcode(c.prog.BinWriter, opcode.SWAP)
+	case 3:
+		emit.Int(c.prog.BinWriter, 2)
+		emit.Opcode(c.prog.BinWriter, opcode.XSWAP)
+	default:
+		for i := 1; i < num; i++ {
+			emit.Int(c.prog.BinWriter, int64(i))
+			emit.Opcode(c.prog.BinWriter, opcode.ROLL)
+		}
+	}
+}
+
 func (c *codegen) getEqualityOpcode(expr ast.Expr) opcode.Opcode {
 	t, ok := c.typeInfo.Types[expr].Type.Underlying().(*types.Basic)
 	if ok && t.Info()&types.IsNumeric != 0 {
@@ -780,6 +786,9 @@ func (c *codegen) convertBuiltin(expr *ast.CallExpr) {
 	case "VerifySignature":
 		emit.Opcode(c.prog.BinWriter, opcode.VERIFY)
 	case "AppCall":
+		numArgs := len(expr.Args) - 1
+		c.emitReverse(numArgs)
+
 		emit.Opcode(c.prog.BinWriter, opcode.APPCALL)
 		buf := c.getByteArray(expr.Args[0])
 		if len(buf) != 20 {
diff --git a/pkg/compiler/interop_test.go b/pkg/compiler/interop_test.go
index 29831477f..2ebc71c29 100644
--- a/pkg/compiler/interop_test.go
+++ b/pkg/compiler/interop_test.go
@@ -2,7 +2,6 @@ package compiler_test
 
 import (
 	"fmt"
-	"math/big"
 	"strings"
 	"testing"
 
@@ -55,10 +54,8 @@ func TestFromAddress(t *testing.T) {
 func TestAppCall(t *testing.T) {
 	srcInner := `
 	package foo
-	func Main(args []interface{}) int {
-		a := args[0].(int)
-		b := args[1].(int)
-		return a + b
+	func Main(a []byte, b []byte) []byte {
+		return append(a, b...)
 	}
 	`
 
@@ -80,7 +77,7 @@ func TestAppCall(t *testing.T) {
 
 		require.NoError(t, v.Run())
 
-		assertResult(t, v, big.NewInt(42))
+		assertResult(t, v, []byte{1, 2, 3, 4})
 	})
 
 	t.Run("missing script", func(t *testing.T) {
@@ -106,11 +103,11 @@ func TestAppCall(t *testing.T) {
 		package foo
 		import "github.com/CityOfZion/neo-go/pkg/interop/engine"
 		const scriptHash = ` + fmt.Sprintf("%#v", string(ih.BytesBE())) + `
-		func Main() int {
-			x := 13
-			y := 29
-			result := engine.AppCall([]byte(scriptHash), []interface{}{x, y})
-			return result.(int)
+		func Main() []byte {
+			x := []byte{1, 2}
+			y := []byte{3, 4}
+			result := engine.AppCall([]byte(scriptHash), x, y)
+			return result.([]byte)
 		}
 		`
 
@@ -119,7 +116,7 @@ func TestAppCall(t *testing.T) {
 
 		require.NoError(t, v.Run())
 
-		assertResult(t, v, big.NewInt(42))
+		assertResult(t, v, []byte{1, 2, 3, 4})
 	})
 }
 
@@ -127,11 +124,11 @@ func getAppCallScript(h string) string {
 	return `
 	package foo
 	import "github.com/CityOfZion/neo-go/pkg/interop/engine"
-	func Main() int {
-		x := 13
-		y := 29
-		result := engine.AppCall(` + h + `, []interface{}{x, y})
-		return result.(int)
+	func Main() []byte {
+		x := []byte{1, 2}
+		y := []byte{3, 4}
+		result := engine.AppCall(` + h + `, x, y)
+		return result.([]byte)
 	}
 	`
 }
diff --git a/pkg/interop/engine/engine.go b/pkg/interop/engine/engine.go
index 3230d4a09..d094e3a43 100644
--- a/pkg/interop/engine/engine.go
+++ b/pkg/interop/engine/engine.go
@@ -29,6 +29,6 @@ func GetEntryScriptHash() []byte {
 }
 
 // AppCall executes script with specified hash using provided arguments.
-func AppCall(scriptHash []byte, args []interface{}) interface{} {
+func AppCall(scriptHash []byte, args ...interface{}) interface{} {
 	return nil
 }