diff --git a/hgdriver/hgdev/hg_scanner_300.cpp b/hgdriver/hgdev/hg_scanner_300.cpp
index e8f5214..19c3c62 100644
--- a/hgdriver/hgdev/hg_scanner_300.cpp
+++ b/hgdriver/hgdev/hg_scanner_300.cpp
@@ -1275,7 +1275,8 @@ int hg_scanner_300::get_device_log(string &log)
 		ret = io_->write_bulk(&usbcb, &size);
 		int touch = 0;
 		std::string buff;
-		int bufsize = usbcb.u32_Count < 512 * 1024 ? usbcb.u32_Count : 512 * 1024;
+		int unitsize = 512 * 1024;
+		int bufsize = usbcb.u32_Count <= unitsize ? usbcb.u32_Count : unitsize;
 		buff.resize(bufsize);
 		while (touch < usbcb.u32_Count)
 		{
@@ -1285,17 +1286,10 @@ int hg_scanner_300::get_device_log(string &log)
 
 			out.write(&buff[0], bufsize);
 			touch += bufsize;
-			bufsize = bufsize > usbcb.u32_Count - touch ? usbcb.u32_Count - touch : bufsize;
+			bufsize = unitsize > usbcb.u32_Count - touch ? usbcb.u32_Count - touch : unitsize;
 		}
 		out.close();
 
-		ofstream f;
-		f.open(save_path, ios::out | ios::trunc);
-		if (!f.is_open())
-			return SCANNER_ERR_CREATE_FILE_FAILED;
-
-		f << buff << endl;
-		f.close();
 		log = save_path;
 	}
 	else