diff --git a/flash-ipmi.hpp b/flash-ipmi.hpp
index 7b60b05..2e6f6f0 100644
--- a/flash-ipmi.hpp
+++ b/flash-ipmi.hpp
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <cstdio>
 #include <string>
 #include <vector>
 
@@ -171,6 +172,17 @@
 
   private:
     /**
+     * Attempt to write the bytes at the offset.
+     *
+     * @param[in] fd - the file stream pointer.
+     * @param[in] offset - the 0-based byte offset into the flash image.
+     * @param[in] bytes - the bytes to write.
+     * @return true on success, false otherwise.
+     */
+    bool writeBlock(std::FILE* fd, uint32_t offset,
+                    const std::vector<uint8_t>& bytes);
+
+    /**
      * Tries to close out everything.
      */
     void closeEverything();