diff --git a/Downstream/Middlewares/ST/STM32_USB_Host_Library/Class/MSC/Src/usbh_msc.c b/Downstream/Middlewares/ST/STM32_USB_Host_Library/Class/MSC/Src/usbh_msc.c
index cf1c477..1578b5c 100644
--- a/Downstream/Middlewares/ST/STM32_USB_Host_Library/Class/MSC/Src/usbh_msc.c
+++ b/Downstream/Middlewares/ST/STM32_USB_Host_Library/Class/MSC/Src/usbh_msc.c
@@ -496,8 +496,10 @@ static USBH_StatusTypeDef USBH_MSC_Process(USBH_HandleTypeDef *phost)
       error = USBH_OK;
       break;
 
-  case MSC_READ:
+#ifdef MASS_STORAGE_WRITES_PERMITTED
   case MSC_WRITE:
+#endif
+  case MSC_READ:
     error = USBH_MSC_RdWrProcess(phost, MSC_Handle->rw_lun);
     if(((int32_t)(phost->Timer - MSC_Handle->timeout) > 0) || (phost->device.is_connected == 0))
     {
@@ -572,6 +574,7 @@ static USBH_StatusTypeDef USBH_MSC_RdWrProcess(USBH_HandleTypeDef *phost, uint8_
 #endif   
     break;     
     
+#ifdef MASS_STORAGE_WRITES_PERMITTED
   case MSC_WRITE: 
     scsi_status = USBH_MSC_SCSI_Write(phost,lun, 0, 0) ;
     
@@ -592,7 +595,8 @@ static USBH_StatusTypeDef USBH_MSC_RdWrProcess(USBH_HandleTypeDef *phost, uint8_
 #if (USBH_USE_OS == 1)
     osMessagePut ( phost->os_event, USBH_CLASS_EVENT, 0);
 #endif       
-    break; 
+    break;
+#endif  //#ifdef MASS_STORAGE_WRITES_PERMITTED
   
   case MSC_REQUEST_SENSE:
     scsi_status = USBH_MSC_SCSI_RequestSense(phost, lun, &MSC_Handle->unit[lun].sense);
@@ -758,6 +762,7 @@ USBH_StatusTypeDef USBH_MSC_Read(USBH_HandleTypeDef *phost,
   * @param  length: number of sector to write
   * @retval USBH Status
   */
+#ifdef MASS_STORAGE_WRITES_PERMITTED
 USBH_StatusTypeDef USBH_MSC_Write(USBH_HandleTypeDef *phost,
                                      uint8_t lun,
                                      uint32_t address,
@@ -786,6 +791,7 @@ USBH_StatusTypeDef USBH_MSC_Write(USBH_HandleTypeDef *phost,
                      length);
   return USBH_OK;
 }
+#endif  //#ifdef MASS_STORAGE_WRITES_PERMITTED
 
 #endif  //#ifdef ENABLE_MASS_STORAGE
 
diff --git a/Downstream/Middlewares/ST/STM32_USB_Host_Library/Class/MSC/Src/usbh_msc_bot.c b/Downstream/Middlewares/ST/STM32_USB_Host_Library/Class/MSC/Src/usbh_msc_bot.c
index 0fab690..4cdbada 100644
--- a/Downstream/Middlewares/ST/STM32_USB_Host_Library/Class/MSC/Src/usbh_msc_bot.c
+++ b/Downstream/Middlewares/ST/STM32_USB_Host_Library/Class/MSC/Src/usbh_msc_bot.c
@@ -301,6 +301,7 @@ USBH_StatusTypeDef USBH_MSC_BOT_Process (USBH_HandleTypeDef *phost, uint8_t lun)
                            MSC_Handle->OutPipe,
                            1);
     }
+#ifdef MASS_STORAGE_WRITES_PERMITTED
     else
     {
         //Asynchronous multi-packet operation: get first packet
@@ -311,6 +312,7 @@ USBH_StatusTypeDef USBH_MSC_BOT_Process (USBH_HandleTypeDef *phost, uint8_t lun)
             MSC_Handle->hbot.state  = BOT_ERROR_OUT;
         }
     }
+#endif
     break;
 
   case BOT_DATA_OUT_WAIT_RECEIVE_PACKET:
@@ -328,6 +330,7 @@ USBH_StatusTypeDef USBH_MSC_BOT_Process (USBH_HandleTypeDef *phost, uint8_t lun)
             //Simple single-buffer operation: everything must fit in one URB
             MSC_Handle->hbot.state = BOT_RECEIVE_CSW;
         }
+#ifdef MASS_STORAGE_WRITES_PERMITTED
         else
         {
             //Asynchronous multi-packet operation
@@ -359,6 +362,7 @@ USBH_StatusTypeDef USBH_MSC_BOT_Process (USBH_HandleTypeDef *phost, uint8_t lun)
                 }
             }
         }
+#endif
     }
     
     else if(URB_Status == USBH_URB_NOTREADY)
@@ -368,6 +372,7 @@ USBH_StatusTypeDef USBH_MSC_BOT_Process (USBH_HandleTypeDef *phost, uint8_t lun)
         {
             MSC_Handle->hbot.state = BOT_DATA_OUT;
         }
+#ifdef MASS_STORAGE_WRITES_PERMITTED
         else
         {
             //Increment counters by the amount of data actually transferred during the NAK'd URB
@@ -378,6 +383,7 @@ USBH_StatusTypeDef USBH_MSC_BOT_Process (USBH_HandleTypeDef *phost, uint8_t lun)
 
             USBH_MSC_BOT_Write_Multipacket_PrepareURB(phost);
         }
+#endif
     }
     
     else if(URB_Status == USBH_URB_STALL)
@@ -516,7 +522,7 @@ void USBH_MSC_BOT_Read_Multipacket_PrepareURB(USBH_HandleTypeDef *phost)
                          MSC_Handle->InPipe);
 }
 
-
+#ifdef MASS_STORAGE_WRITES_PERMITTED
 void USBH_MSC_BOT_Write_Multipacket_ReceivePacketCallback(DownstreamPacketTypeDef* receivedPacket,
                                                           uint16_t dataLength)
 {
@@ -558,7 +564,7 @@ void USBH_MSC_BOT_Write_Multipacket_PrepareURB(USBH_HandleTypeDef *phost)
                        MSC_Handle->OutPipe,
                        1);
 }
-
+#endif
 
 /**
   * @brief  USBH_MSC_BOT_Abort 
@@ -570,6 +576,7 @@ void USBH_MSC_BOT_Write_Multipacket_PrepareURB(USBH_HandleTypeDef *phost)
   */
 static USBH_StatusTypeDef USBH_MSC_BOT_Abort(USBH_HandleTypeDef *phost, uint8_t lun, uint8_t dir)
 {
+  UNUSED(lun);
   USBH_StatusTypeDef status = USBH_FAIL;
   MSC_HandleTypeDef *MSC_Handle =  (MSC_HandleTypeDef *) phost->pActiveClass->pData;
   
diff --git a/Downstream/Middlewares/ST/STM32_USB_Host_Library/Class/MSC/Src/usbh_msc_scsi.c b/Downstream/Middlewares/ST/STM32_USB_Host_Library/Class/MSC/Src/usbh_msc_scsi.c
index 79b3ee1..86bf95f 100644
--- a/Downstream/Middlewares/ST/STM32_USB_Host_Library/Class/MSC/Src/usbh_msc_scsi.c
+++ b/Downstream/Middlewares/ST/STM32_USB_Host_Library/Class/MSC/Src/usbh_msc_scsi.c
@@ -325,6 +325,7 @@ USBH_StatusTypeDef USBH_MSC_SCSI_RequestSense (USBH_HandleTypeDef *phost,
   * @param  length: number of sector to write
   * @retval USBH Status
   */
+#ifdef MASS_STORAGE_WRITES_PERMITTED
 USBH_StatusTypeDef USBH_MSC_SCSI_Write(USBH_HandleTypeDef *phost,
                                      uint8_t lun,
                                      uint32_t address,
@@ -372,6 +373,7 @@ USBH_StatusTypeDef USBH_MSC_SCSI_Write(USBH_HandleTypeDef *phost,
   
   return error;
 }
+#endif
 
 /**
   * @brief  USBH_MSC_SCSI_Read 
diff --git a/Downstream/Src/downstream_msc.c b/Downstream/Src/downstream_msc.c
index 4a14a81..eebe723 100644
--- a/Downstream/Src/downstream_msc.c
+++ b/Downstream/Src/downstream_msc.c
@@ -80,9 +80,11 @@ void Downstream_MSC_PacketProcessor(DownstreamPacketTypeDef* receivedPacket)
         Downstream_MSC_PacketProcessor_BeginRead(receivedPacket);
         break;
 
+#ifdef MASS_STORAGE_WRITES_PERMITTED
     case COMMAND_MSC_WRITE:
         Downstream_MSC_PacketProcessor_BeginWrite(receivedPacket);
         break;
+#endif
 
     default:
         Downstream_PacketProcessor_FreakOut();
@@ -170,7 +172,7 @@ void Downstream_MSC_PacketProcessor_RdWrCompleteCallback(USBH_StatusTypeDef resu
 }
 
 
-
+#ifdef MASS_STORAGE_WRITES_PERMITTED
 void Downstream_MSC_PacketProcessor_BeginWrite(DownstreamPacketTypeDef* receivedPacket)
 {
     uint64_t writeBlockAddress;
@@ -217,6 +219,7 @@ void Downstream_MSC_PacketProcessor_BeginWrite(DownstreamPacketTypeDef* received
     }
     Downstream_TransmitPacket(receivedPacket);
 }
+#endif
 
 
 //Used by USB MSC host driver
@@ -235,6 +238,7 @@ HAL_StatusTypeDef Downstream_MSC_PutStreamDataPacket(DownstreamPacketTypeDef* pa
 }
 
 
+#ifdef MASS_STORAGE_WRITES_PERMITTED
 //Used by USB MSC host driver
 HAL_StatusTypeDef Downstream_MSC_GetStreamDataPacket(DownstreamMSCCallbackPacketTypeDef callback)
 {
@@ -286,6 +290,7 @@ void Downstream_MSC_GetStreamDataPacketCallback(DownstreamPacketTypeDef* receive
     }
 
 }
+#endif  //#ifdef MASS_STORAGE_WRITES_PERMITTED
 
 #endif  //#ifdef ENABLE_MASS_STORAGE