diff --git a/include/smbioshandler.hpp b/include/smbioshandler.hpp
index 40e081f..4e403ca 100644
--- a/include/smbioshandler.hpp
+++ b/include/smbioshandler.hpp
@@ -60,6 +60,12 @@
     MDRState State;
 } __attribute__((packed));
 
+struct RegionCompleteRequest
+{
+    uint8_t sessionId;
+    uint8_t regionId;
+} __attribute__((packed));
+
 struct RegionReadRequest
 {
     uint8_t regionId;
@@ -74,4 +80,21 @@
     uint8_t data[msgPayloadSize];
 } __attribute__((packed));
 
+struct RegionWriteRequest
+{
+    uint8_t sessionId;
+    uint8_t regionId;
+    uint8_t length;
+    uint16_t offset;
+    uint8_t data[msgPayloadSize];
+} __attribute__((packed));
+
+struct RegionLockRequest
+{
+    uint8_t sessionId;
+    uint8_t regionId;
+    uint8_t lockPolicy;
+    uint16_t msTimeout;
+} __attribute__((packed));
+
 constexpr size_t maxMDRId = 5;
diff --git a/src/smbioshandler.cpp b/src/smbioshandler.cpp
index 0c288b1..9eebf7f 100644
--- a/src/smbioshandler.cpp
+++ b/src/smbioshandler.cpp
@@ -34,7 +34,6 @@
 constexpr const char* DBUS_PROPERTIES = "org.freedesktop.DBus.Properties";
 constexpr const char* MDRV1_PATH = "/xyz/openbmc_project/Smbios/MDR_V1";
 constexpr const char* MDRV1_INTERFACE = "xyz.openbmc_project.Smbios.MDR_V1";
-static constexpr const uint8_t ccOemSetInProcess = 0x81;
 
 static void register_netfn_smbios_functions() __attribute__((constructor));
 
@@ -126,62 +125,63 @@
     return 0;
 }
 
-/** @brief implements bmc region update Complete command
- *  @param sessionId - session Lock Handle
- *  @param regionId - data Region
- *
- *  @returns IPMI completion code
- */
-ipmi::RspType<> bmcRegionUpdateComplete(uint8_t sessionId, uint8_t regionId)
+ipmi_ret_t cmd_region_complete(ipmi_netfn_t netfn, ipmi_cmd_t cmd,
+                               ipmi_request_t request, ipmi_response_t response,
+                               ipmi_data_len_t data_len, ipmi_context_t context)
 {
-    std::variant<uint8_t, uint16_t> value;
+    auto requestData = reinterpret_cast<const RegionCompleteRequest*>(request);
+    uint8_t status;
 
-    if ((regionId >= maxMDRId) || (regionId == 0))
+    sdbusplus::message::variant<uint8_t, uint16_t> value;
+
+    if (*data_len != sizeof(RegionCompleteRequest))
+    {
+        *data_len = 0;
+        return IPMI_CC_REQ_DATA_LEN_INVALID;
+    }
+
+    uint8_t regionId = requestData->regionId - 1;
+    *data_len = 0;
+
+    if (regionId >= maxMDRId)
     {
         phosphor::logging::log<level::ERR>("Invalid region");
-        return ipmi::responseParmOutOfRange();
+        return IPMI_CC_PARM_OUT_OF_RANGE;
     }
 
     std::shared_ptr<sdbusplus::asio::connection> bus = getSdBus();
     std::string service = ipmi::getService(*bus, MDRV1_INTERFACE, MDRV1_PATH);
 
-    uint8_t regionIdLocal = regionId - 1;
-
-    if (regionIdLocal == 0)
-    {
-        phosphor::logging::log<level::ERR>("Invalid region");
-        return ipmi::responseParmOutOfRange();
-    }
-    if (set_regionId(regionIdLocal, service) < 0)
+    if (set_regionId(regionId, service) < 0)
     {
         phosphor::logging::log<level::ERR>("Error setting regionId");
-        return ipmi::responseUnspecifiedError();
+        return IPMI_CC_UNSPECIFIED_ERROR;
     }
 
     if (0 > sdplus_mdrv1_get_property("LockPolicy", value, service))
     {
         phosphor::logging::log<level::ERR>("Error getting lockPolicy");
-        return ipmi::responseUnspecifiedError();
+        return IPMI_CC_UNSPECIFIED_ERROR;
     }
     if (regionLockUnlocked == std::get<uint8_t>(value))
     {
-        return ipmi::responseCommandNotAvailable();
+        return IPMI_CC_PARAMETER_NOT_SUPPORT_IN_PRESENT_STATE;
     }
 
     if (0 > sdplus_mdrv1_get_property("SessionId", value, service))
     {
         phosphor::logging::log<level::ERR>("Error getting sessionId");
-        return ipmi::responseUnspecifiedError();
+        return IPMI_CC_UNSPECIFIED_ERROR;
     }
-    if (sessionId != std::get<uint8_t>(value))
+    if (requestData->sessionId != std::get<uint8_t>(value))
     {
-        return ipmi::response(ccOemSetInProcess);
+        return IPMI_CC_OEM_SET_IN_PROCESS;
     }
 
     auto method = bus->new_method_call(service.c_str(), MDRV1_PATH,
                                        MDRV1_INTERFACE, "RegionComplete");
 
-    method.append(regionIdLocal);
+    method.append(regionId);
 
     auto reply = bus->call(method);
     if (reply.is_method_error())
@@ -190,19 +190,16 @@
             "Error set region complete",
             phosphor::logging::entry("SERVICE=%s", service.c_str()),
             phosphor::logging::entry("PATH=%s", MDRV1_PATH));
-        return ipmi::responseUnspecifiedError();
+        return IPMI_CC_UNSPECIFIED_ERROR;
     }
-    uint8_t status = 0;
     reply.read(status);
 
     if (status != 0)
-    {
         phosphor::logging::log<level::ERR>(
             "Error set region complete, unexpected error");
-        return ipmi::responseUnspecifiedError();
-    }
+    return IPMI_CC_UNSPECIFIED_ERROR;
 
-    return ipmi::responseSuccess();
+    return IPMI_CC_OK;
 }
 
 ipmi_ret_t cmd_region_read(ipmi_netfn_t netfn, ipmi_cmd_t cmd,
@@ -293,64 +290,71 @@
     return IPMI_CC_OK;
 }
 
-/** @brief implements bmc region write command
- *  @parameter
- *   - sessionId - session Lock Handle
- *   - regionId - data Region
- *   - length - data Length
- *   - offset - data Offset
- *   - data - data to be written
- *
- *  @returns IPMI completion code plus response data
- *   - writeData - contains data Region, valid Data,
- *                 lock Status, max Region Length, region Used (in bytes)
- */
-ipmi::RspType<std::vector<uint8_t>>
-    bmcRegionWrite(uint8_t sessionId, uint8_t regionId, uint8_t length,
-                   uint16_t offset, std::vector<uint8_t> data)
+ipmi_ret_t cmd_region_write(ipmi_netfn_t netfn, ipmi_cmd_t cmd,
+                            ipmi_request_t request, ipmi_response_t response,
+                            ipmi_data_len_t data_len, ipmi_context_t context)
 {
-    std::variant<uint8_t, uint16_t> value;
+    auto requestData = reinterpret_cast<const RegionWriteRequest*>(request);
+    uint8_t regionId = requestData->regionId - 1;
+    std::string res;
+    std::vector<uint8_t> writeData;
+    uint16_t index;
+    uint8_t tmp[255];
 
-    if ((regionId >= maxMDRId) || (regionId == 0))
+    size_t minInputLen = &requestData->data[0] - &requestData->sessionId + 1;
+    if (*data_len < minInputLen)
+    { // this command need at least 6 bytes input
+        *data_len = 0;
+        return IPMI_CC_REQ_DATA_LEN_INVALID;
+    }
+
+    sdbusplus::message::variant<uint8_t, uint16_t> value;
+
+    *data_len = 0;
+
+    if (regionId >= maxMDRId)
     {
         phosphor::logging::log<level::ERR>("Invalid region");
-        return ipmi::responseParmOutOfRange();
+        return IPMI_CC_PARM_OUT_OF_RANGE;
     }
 
     std::shared_ptr<sdbusplus::asio::connection> bus = getSdBus();
     std::string service = ipmi::getService(*bus, MDRV1_INTERFACE, MDRV1_PATH);
 
-    uint8_t regionIdLocal = regionId - 1;
-
-    if (set_regionId(regionIdLocal, service) < 0)
+    if (set_regionId(regionId, service) < 0)
     {
         phosphor::logging::log<level::ERR>("Error setting regionId");
-        return ipmi::responseUnspecifiedError();
+        return IPMI_CC_UNSPECIFIED_ERROR;
     }
 
     if (0 > sdplus_mdrv1_get_property("LockPolicy", value, service))
     {
         phosphor::logging::log<level::ERR>("Error getting lockPolicy");
-        return ipmi::responseUnspecifiedError();
+        return IPMI_CC_UNSPECIFIED_ERROR;
     }
     if (regionLockUnlocked == std::get<uint8_t>(value))
     {
-        return ipmi::responseCommandNotAvailable();
+        return IPMI_CC_PARAMETER_NOT_SUPPORT_IN_PRESENT_STATE;
     }
 
     if (0 > sdplus_mdrv1_get_property("SessionId", value, service))
     {
         phosphor::logging::log<level::ERR>("Error getting sessionId");
-        return ipmi::responseUnspecifiedError();
+        return IPMI_CC_UNSPECIFIED_ERROR;
     }
-    if (sessionId != std::get<uint8_t>(value))
+    if (requestData->sessionId != std::get<uint8_t>(value))
     {
-        return ipmi::response(ccOemSetInProcess);
+        return IPMI_CC_OEM_SET_IN_PROCESS;
     }
 
-    std::vector<uint8_t> writeData;
-    std::copy(data.begin(), data.begin() + length,
-              writeData.data() + sizeof(regionIdLocal) + sizeof(length));
+    std::copy(&(requestData->length), &(requestData->data[requestData->length]),
+              tmp);
+    writeData.push_back(regionId);
+    for (index = 0; index < minInputLen + requestData->length - 2; index++)
+    {
+        writeData.push_back(tmp[index]);
+    }
+
     auto method = bus->new_method_call(service.c_str(), MDRV1_PATH,
                                        MDRV1_INTERFACE, "RegionWrite");
 
@@ -363,68 +367,67 @@
             "Error write region data",
             phosphor::logging::entry("SERVICE=%s", service.c_str()),
             phosphor::logging::entry("PATH=%s", MDRV1_PATH));
-        return ipmi::responseUnspecifiedError();
+        return IPMI_CC_UNSPECIFIED_ERROR;
     }
-    std::string res;
     reply.read(res);
 
     if (res == "NoData")
     {
-        return ipmi::responseParmOutOfRange();
+        return IPMI_CC_PARM_OUT_OF_RANGE;
     }
     else if (res != "Success")
     {
         phosphor::logging::log<level::ERR>(
             "Error write region data, unexpected error");
-        return ipmi::responseUnspecifiedError();
+        return IPMI_CC_UNSPECIFIED_ERROR;
     }
 
-    return ipmi::responseSuccess(writeData);
+    return IPMI_CC_OK;
 }
 
-/** @brief implements bmc region lock command
- *  @parameter
- *   - sessionId - session Lock Handle
- *   - regionId - data Region
- *   - lockPolicy - Lock Type
- *   - msTimeout - timeout. Number of milliseconds allowed before lock is
- * released
- *
- *  @returns IPMI completion code plus response data
- *   - lockResponse - session Lock Handle
- */
-ipmi::RspType<uint8_t> // lockResponse
-    bmcRegionLock(uint8_t sessionId, uint8_t regionId, uint8_t lockPolicy,
-                  uint16_t msTimeout)
+ipmi_ret_t cmd_region_lock(ipmi_netfn_t netfn, ipmi_cmd_t cmd,
+                           ipmi_request_t request, ipmi_response_t response,
+                           ipmi_data_len_t data_len, ipmi_context_t context)
 {
-    std::variant<uint8_t, uint16_t> value;
+    auto requestData = reinterpret_cast<const RegionLockRequest*>(request);
+    uint8_t regionId = requestData->regionId - 1;
+    sdbusplus::message::variant<uint8_t, uint16_t> value;
+    auto res = reinterpret_cast<uint8_t*>(response);
+    uint8_t lockResponse;
 
-    if ((regionId >= maxMDRId) || (regionId == 0))
+    if (*data_len != sizeof(RegionLockRequest))
+    {
+        *data_len = 0;
+        return IPMI_CC_REQ_DATA_LEN_INVALID;
+    }
+
+    *data_len = 0;
+
+    if (regionId >= maxMDRId)
     {
         phosphor::logging::log<level::ERR>("Invalid region");
-        return ipmi::responseParmOutOfRange();
+        return IPMI_CC_PARM_OUT_OF_RANGE;
     }
 
     std::shared_ptr<sdbusplus::asio::connection> bus = getSdBus();
     std::string service = ipmi::getService(*bus, MDRV1_INTERFACE, MDRV1_PATH);
 
-    uint8_t regionIdLocal = regionId - 1;
-    if (set_regionId(regionIdLocal, service) < 0)
+    if (set_regionId(regionId, service) < 0)
     {
         phosphor::logging::log<level::ERR>("Error setting regionId");
-        return ipmi::responseUnspecifiedError();
+        return IPMI_CC_UNSPECIFIED_ERROR;
     }
 
     if (0 > sdplus_mdrv1_get_property("LockPolicy", value, service))
     {
         phosphor::logging::log<level::ERR>("Error getting lockPolicy");
-        return ipmi::responseUnspecifiedError();
+        return IPMI_CC_UNSPECIFIED_ERROR;
     }
-    if (lockPolicy == regionLockUnlocked)
+    if (requestData->lockPolicy == regionLockUnlocked)
     {
         if (regionLockUnlocked == std::get<uint8_t>(value))
         {
-            return ipmi::responseCommandNotAvailable();
+            return IPMI_CC_PARAMETER_NOT_SUPPORT_IN_PRESENT_STATE;
         }
     }
     if (regionLockUnlocked != std::get<uint8_t>(value))
@@ -432,20 +435,21 @@
         if (0 > sdplus_mdrv1_get_property("SessionId", value, service))
         {
             phosphor::logging::log<level::ERR>("Error getting sessionId");
-            return ipmi::responseUnspecifiedError();
+            return IPMI_CC_UNSPECIFIED_ERROR;
         }
-        if (sessionId != std::get<uint8_t>(value))
+        if (requestData->sessionId != std::get<uint8_t>(value))
         {
-            if (lockPolicy != regionLockStrict)
+            if (requestData->lockPolicy != regionLockStrict)
             {
-                return ipmi::response(ccOemSetInProcess);
+                return IPMI_CC_OEM_SET_IN_PROCESS;
             }
         }
     }
     auto method = bus->new_method_call(service.c_str(), MDRV1_PATH,
                                        MDRV1_INTERFACE, "RegionLock");
 
-    method.append(sessionId, regionIdLocal, lockPolicy, msTimeout);
+    method.append(requestData->sessionId, regionId, requestData->lockPolicy,
+                  requestData->msTimeout);
 
     auto reply = bus->call(method);
     if (reply.is_method_error())
@@ -454,12 +458,13 @@
             "Error lock region ",
             phosphor::logging::entry("SERVICE=%s", service.c_str()),
             phosphor::logging::entry("PATH=%s", MDRV1_PATH));
-        return ipmi::responseUnspecifiedError();
+        return IPMI_CC_UNSPECIFIED_ERROR;
     }
-    uint8_t lockResponse = 0;
     reply.read(lockResponse);
 
-    return ipmi::responseSuccess(lockResponse);
+    *data_len = sizeof(lockResponse);
+    *res = lockResponse;
+    return IPMI_CC_OK;
 }
 
 static void register_netfn_smbios_functions(void)
@@ -471,9 +476,9 @@
                            cmd_region_status, PRIVILEGE_OPERATOR);
 
     // <Update Complete Status Command>
-    ipmi::registerHandler(ipmi::prioOemBase, NETFUN_INTEL_APP_OEM,
-                          IPMI_NETFN_INTEL_OEM_APP_CMD::MDR_COMPLETE,
-                          ipmi::Privilege::Operator, bmcRegionUpdateComplete);
+    ipmi_register_callback(NETFUN_INTEL_APP_OEM,
+                           IPMI_NETFN_INTEL_OEM_APP_CMD::MDR_COMPLETE, NULL,
+                           cmd_region_complete, PRIVILEGE_OPERATOR);
 
     // <Read MDR Command>
     ipmi_register_callback(NETFUN_INTEL_APP_OEM,
@@ -481,12 +486,12 @@
                            cmd_region_read, PRIVILEGE_OPERATOR);
 
     // <Write MDR Command>
-    ipmi::registerHandler(ipmi::prioOemBase, NETFUN_INTEL_APP_OEM,
-                          IPMI_NETFN_INTEL_OEM_APP_CMD::MDR_WRITE,
-                          ipmi::Privilege::Operator, bmcRegionWrite);
+    ipmi_register_callback(NETFUN_INTEL_APP_OEM,
+                           IPMI_NETFN_INTEL_OEM_APP_CMD::MDR_WRITE, NULL,
+                           cmd_region_write, PRIVILEGE_OPERATOR);
 
     // <Lock MDR Command>
-    ipmi::registerHandler(ipmi::prioOemBase, NETFUN_INTEL_APP_OEM,
-                          IPMI_NETFN_INTEL_OEM_APP_CMD::MDR_LOCK,
-                          ipmi::Privilege::Operator, bmcRegionLock);
+    ipmi_register_callback(NETFUN_INTEL_APP_OEM,
+                           IPMI_NETFN_INTEL_OEM_APP_CMD::MDR_LOCK, NULL,
+                           cmd_region_lock, PRIVILEGE_OPERATOR);
 }