diff --git a/app/src/main/cpp/PhoneDevice.cpp b/app/src/main/cpp/PhoneDevice.cpp
index b918767f..f06c8db7 100644
--- a/app/src/main/cpp/PhoneDevice.cpp
+++ b/app/src/main/cpp/PhoneDevice.cpp
@@ -1592,8 +1592,10 @@ bool CPhoneDevice::OnImageReady(cv::Mat& mat)
         if (mPhotoInfo.retries < (DEFAULT_TAKE_PHOTO_RETRIES - 1))
         {
             shouldRetry = true;
+            char presetBuf[16] = { 0 };
+            snprintf(presetBuf, sizeof(presetBuf), "%02X", mPhotoInfo.retries);
             // replaceAll(fullPath, ".jpg", std::string("-") + std::to_string(mPhotoInfo.retries) + ".jpg");
-            replaceAll(fullPath, "_FF_", std::string("_") + std::to_string(mPhotoInfo.retries) + std::string("_"));
+            replaceAll(fullPath, "_FF_", std::string("_") + presetBuf + std::string("_"));
             XYLOG(XYLOG_SEVERITY_ERROR, "Photo is TOO dark or light(LDR=%u), will RETRY it", (uint32_t)captureResult.avgY);
         }