diff --git a/binary/reflect.go b/binary/reflect.go
index c745b6157..f23acb385 100644
--- a/binary/reflect.go
+++ b/binary/reflect.go
@@ -66,7 +66,7 @@ func (info StructFieldInfo) unpack() (int, reflect.Type, Options) {
 	return info.Index, info.Type, info.Options
 }
 
-// e.g. If o is struct{Foo}{}, return is the Foo interface type.
+// e.g. If o is struct{Foo}{}, return is the Foo reflection type.
 func GetTypeFromStructDeclaration(o interface{}) reflect.Type {
 	rt := reflect.TypeOf(o)
 	if rt.NumField() != 1 {
diff --git a/types/tx_utils.go b/types/tx_utils.go
index b0f87f029..a4ba02de0 100644
--- a/types/tx_utils.go
+++ b/types/tx_utils.go
@@ -206,7 +206,7 @@ func NewUnbondTx(addr []byte, height uint) *UnbondTx {
 }
 
 func (tx *UnbondTx) Sign(chainID string, privAccount *account.PrivAccount) {
-	tx.Signature = privAccount.Sign(chainID, tx)
+	tx.Signature = privAccount.Sign(chainID, tx).(account.SignatureEd25519)
 }
 
 //----------------------------------------------------------------------
@@ -220,5 +220,5 @@ func NewRebondTx(addr []byte, height uint) *RebondTx {
 }
 
 func (tx *RebondTx) Sign(chainID string, privAccount *account.PrivAccount) {
-	tx.Signature = privAccount.Sign(chainID, tx)
+	tx.Signature = privAccount.Sign(chainID, tx).(account.SignatureEd25519)
 }