diff --git a/src/fsfw/cfdp/tlv/ReservedMessageCreator.cpp b/src/fsfw/cfdp/tlv/ReservedMessageCreator.cpp
index a4ce0a99..5eaf72c6 100644
--- a/src/fsfw/cfdp/tlv/ReservedMessageCreator.cpp
+++ b/src/fsfw/cfdp/tlv/ReservedMessageCreator.cpp
@@ -3,18 +3,32 @@
 cfdp::ReservedMessageCreator::ReservedMessageCreator(uint8_t messageType, uint8_t *msgData,
                                                      size_t msgLen)
     : messageType(messageType), msgData(msgData), msgSize(msgLen) {}
+
 ReturnValue_t cfdp::ReservedMessageCreator::serialize(
     uint8_t **buffer, size_t *size, size_t maxSize,
     SerializeIF::Endianness streamEndianness) const {
   if (*size + getSerializedSize() > maxSize) {
     return SerializeIF::BUFFER_TOO_SHORT;
   }
+  **buffer = TlvType::MSG_TO_USER;
+  *buffer += 1;
+  *size += 1;
+  **buffer = getSerializedSize() - 1;
+  *size += 1;
+  *buffer += 1;
+  std::memcpy(*buffer, MSG_HEADER, 4);
+  *buffer += 4;
+  *size += 4;
+  **buffer = messageType;
+  *buffer += 1;
+  *size += 1;
+  std::memcpy(*buffer, msgData, msgSize);
   return returnvalue::OK;
 }
 
 size_t cfdp::ReservedMessageCreator::getSerializedSize() const {
-  // 3 bytes type and length and value, 4 bytes CFDP, 1 byte reserved message type, message data.
-  return 3 + 5 + msgSize;
+  // 2 bytes type and length, 4 bytes CFDP, 1 byte reserved message type, message data.
+  return 2 + 5 + msgSize;
 }
 
 ReturnValue_t cfdp::ReservedMessageCreator::deSerialize(const uint8_t **buffer, size_t *size,
diff --git a/src/fsfw/cfdp/tlv/ReservedMessageCreator.h b/src/fsfw/cfdp/tlv/ReservedMessageCreator.h
index 89878635..363791c8 100644
--- a/src/fsfw/cfdp/tlv/ReservedMessageCreator.h
+++ b/src/fsfw/cfdp/tlv/ReservedMessageCreator.h
@@ -6,6 +6,8 @@ namespace cfdp {
 
 class ReservedMessageCreator : public SerializeIF {
  public:
+  static constexpr char MSG_HEADER[] = "cfdp";
+
   ReservedMessageCreator(uint8_t messageType, uint8_t *msgData, size_t msgLen);
   [[nodiscard]] ReturnValue_t serialize(uint8_t **buffer, size_t *size, size_t maxSize,
                                         Endianness streamEndianness) const override;