diff --git a/flash-ipmi.hpp b/flash-ipmi.hpp
index 43cafe1..deef582 100644
--- a/flash-ipmi.hpp
+++ b/flash-ipmi.hpp
@@ -1,5 +1,10 @@
 #pragma once
 
+#include "host-ipmid/ipmid-api.h"
+
+/* Clearer way to represent the subcommand size. */
+#define SUBCMD_SZ sizeof(uint8_t)
+
 /*
  * flashStartTransfer -- starts file upload.
  * flashDataBlock -- adds data to image file.
@@ -55,3 +60,52 @@
     flashHashExtData = 12,
     flashMapRegionLpc = 13,
 };
+
+/*
+ * StartTransfer expects a basic structure providing some information.
+ */
+struct StartTx
+{
+    uint8_t cmd;
+    uint32_t length; /* Maximum image length is 4GiB (little-endian) */
+} __attribute__((packed));
+
+class UpdateInterface
+{
+  public:
+    virtual ~UpdateInterface() = default;
+
+    virtual bool start(uint32_t length) = 0;
+};
+
+class FlashUpdate : public UpdateInterface
+{
+  public:
+    FlashUpdate() = default;
+    ~FlashUpdate() = default;
+    FlashUpdate(const FlashUpdate&) = default;
+    FlashUpdate& operator=(const FlashUpdate&) = default;
+    FlashUpdate(FlashUpdate&&) = default;
+    FlashUpdate& operator=(FlashUpdate&&) = default;
+
+    /**
+     * Prepare to receive a BMC image and then a signature.
+     *
+     * @param[in] length - the size of the flash image.
+     * @return true on success, false otherwise.
+     */
+    bool start(uint32_t length) override;
+
+  private:
+    /**
+     * Tries to close out and delete anything staged.
+     */
+    void abortEverything();
+
+    /**
+     * Open all staged file handles you expect to use.
+     *
+     * @return false on failure.
+     */
+    bool openEverything();
+};