diff --git a/common/blockchain/rpc.go b/common/blockchain/rpc.go
index b2d7153..be53a5f 100644
--- a/common/blockchain/rpc.go
+++ b/common/blockchain/rpc.go
@@ -62,13 +62,14 @@ func WaitForReceipt(client *web3go.Client, txHash common.Hash, successRequired b
 	if len(opts) > 0 {
 		opt = opts[0]
 	} else {
+		// default infinite wait
 		opt.Rounds = 0
-		opt.Interval = time.Second
+		opt.Interval = time.Second * 3
 	}
 
 	var tries uint
 	for receipt == nil {
-		if tries > opt.Rounds+1 {
+		if tries > opt.Rounds+1 && opt.Rounds != 0 {
 			return nil, errors.New("no receipt after max retries")
 		}
 		time.Sleep(opt.Interval)
diff --git a/transfer/uploader.go b/transfer/uploader.go
index 5d2c405..9e079ac 100644
--- a/transfer/uploader.go
+++ b/transfer/uploader.go
@@ -111,7 +111,7 @@ func (uploader *Uploader) BatchUpload(datas []core.IterableData, waitForLogEntry
 	var txHash common.Hash
 	if len(toSubmitDatas) > 0 {
 		var err error
-		if txHash, _, err = uploader.submitLogEntry(toSubmitDatas, toSubmitTags, waitForLogEntry); err != nil {
+		if txHash, _, err = uploader.SubmitLogEntry(toSubmitDatas, toSubmitTags, waitForLogEntry); err != nil {
 			return common.Hash{}, nil, errors.WithMessage(err, "Failed to submit log entry")
 		}
 		if waitForLogEntry {
@@ -124,7 +124,7 @@ func (uploader *Uploader) BatchUpload(datas []core.IterableData, waitForLogEntry
 
 	for i := 0; i < n; i++ {
 		// Upload file to storage node
-		if err := uploader.uploadFile(datas[i], trees[i], 0, opts[i].Disperse, opts[i].TaskSize); err != nil {
+		if err := uploader.UploadFile(datas[i], trees[i], 0, opts[i].Disperse, opts[i].TaskSize); err != nil {
 			return common.Hash{}, nil, errors.WithMessage(err, "Failed to upload file")
 		}
 
@@ -192,7 +192,7 @@ func (uploader *Uploader) Upload(data core.IterableData, option ...UploadOption)
 	segNum := uint64(0)
 	if info == nil {
 		// Append log on blockchain
-		if _, _, err = uploader.submitLogEntry([]core.IterableData{data}, [][]byte{opt.Tags}, true); err != nil {
+		if _, _, err = uploader.SubmitLogEntry([]core.IterableData{data}, [][]byte{opt.Tags}, true); err != nil {
 			return errors.WithMessage(err, "Failed to submit log entry")
 		}
 
@@ -215,7 +215,7 @@ func (uploader *Uploader) Upload(data core.IterableData, option ...UploadOption)
 	}
 
 	// Upload file to storage node
-	if err = uploader.uploadFile(data, tree, segNum, opt.Disperse, opt.TaskSize); err != nil {
+	if err = uploader.UploadFile(data, tree, segNum, opt.Disperse, opt.TaskSize); err != nil {
 		return errors.WithMessage(err, "Failed to upload file")
 	}
 
@@ -229,7 +229,7 @@ func (uploader *Uploader) Upload(data core.IterableData, option ...UploadOption)
 	return nil
 }
 
-func (uploader *Uploader) submitLogEntry(datas []core.IterableData, tags [][]byte, waitForReceipt bool) (common.Hash, *types.Receipt, error) {
+func (uploader *Uploader) SubmitLogEntry(datas []core.IterableData, tags [][]byte, waitForReceipt bool) (common.Hash, *types.Receipt, error) {
 	// Construct submission
 	submissions := make([]contract.Submission, len(datas))
 	for i := 0; i < len(datas); i++ {
@@ -298,7 +298,7 @@ func (uploader *Uploader) waitForLogEntry(root common.Hash, finalityRequired boo
 }
 
 // TODO error tolerance
-func (uploader *Uploader) uploadFile(data core.IterableData, tree *merkle.Tree, segIndex uint64, disperse bool, taskSize uint) error {
+func (uploader *Uploader) UploadFile(data core.IterableData, tree *merkle.Tree, segIndex uint64, disperse bool, taskSize uint) error {
 	stageTimer := time.Now()
 
 	if taskSize == 0 {
diff --git a/transfer/uploader_dup_file.go b/transfer/uploader_dup_file.go
index b71923f..76960bf 100644
--- a/transfer/uploader_dup_file.go
+++ b/transfer/uploader_dup_file.go
@@ -19,7 +19,7 @@ const SubmitEventHash = "0x167ce04d2aa1981994d3a31695da0d785373335b1078cec239a1a
 // file finality on storage node.
 func (uploader *Uploader) uploadDuplicatedFile(data core.IterableData, tags []byte, root common.Hash) error {
 	// submit transaction on blockchain
-	_, receipt, err := uploader.submitLogEntry([]core.IterableData{data}, [][]byte{tags}, true)
+	_, receipt, err := uploader.SubmitLogEntry([]core.IterableData{data}, [][]byte{tags}, true)
 	if err != nil {
 		return errors.WithMessage(err, "Failed to submit log entry")
 	}