diff --git a/Downstream/Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_dma.c b/Downstream/Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_dma.c
index b899d85..e138c6a 100644
--- a/Downstream/Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_dma.c
+++ b/Downstream/Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_dma.c
@@ -407,7 +407,7 @@ HAL_StatusTypeDef HAL_DMA_Start_IT(DMA_HandleTypeDef *hdma, uint32_t SrcAddress,
   __HAL_DMA_ENABLE_IT(hdma, DMA_IT_TC);
 
   /* Enable the Half transfer complete interrupt */
-  __HAL_DMA_ENABLE_IT(hdma, DMA_IT_HT);  
+//  __HAL_DMA_ENABLE_IT(hdma, DMA_IT_HT);
 
   /* Enable the transfer Error interrupt */
   __HAL_DMA_ENABLE_IT(hdma, DMA_IT_TE);
diff --git a/Downstream/Inc/interrupts.h b/Downstream/Inc/interrupts.h
index 2ae4ba4..1dd3f3c 100644
--- a/Downstream/Inc/interrupts.h
+++ b/Downstream/Inc/interrupts.h
@@ -46,9 +46,9 @@
 /* Exported constants --------------------------------------------------------*/
 
 #define INT_PRIORITY_SYSTICK	2
-//#define INT_PRIORITY_SPI_DMA	10
-#define INT_PRIORITY_SPI		8			//Interrupt-based SPI must be highest priority!
-#define INT_PRIORITY_OTG_FS		10
+#define INT_PRIORITY_SPI_DMA	10
+//#define INT_PRIORITY_SPI		8			//Interrupt-based SPI must be highest priority!
+#define INT_PRIORITY_USB		10
 
 
  /* Exported macro ------------------------------------------------------------*/
diff --git a/Downstream/Src/downstream_spi.c b/Downstream/Src/downstream_spi.c
index 48adc16..21a3325 100644
--- a/Downstream/Src/downstream_spi.c
+++ b/Downstream/Src/downstream_spi.c
@@ -177,10 +177,10 @@ void Downstream_PrepareReceivePacketSize(DownstreamPacketTypeDef* freePacket)
 	}
 	CurrentWorkingPacket = freePacket;
 	CurrentWorkingPacket->Length16 = 0;
-	if (HAL_SPI_TransmitReceive_IT(&Hspi1,
-								   (uint8_t*)&CurrentWorkingPacket->Length16,
-								   (uint8_t*)&CurrentWorkingPacket->Length16,
-								   2) != HAL_OK)		//We only need to read one word, but the peripheral library freaks out...
+	if (HAL_SPI_TransmitReceive_DMA(&Hspi1,
+								    (uint8_t*)&CurrentWorkingPacket->Length16,
+								    (uint8_t*)&CurrentWorkingPacket->Length16,
+								    2) != HAL_OK)		//We only need to read one word, but the peripheral library freaks out...
 	{
 		DOWNSTREAM_SPI_FREAKOUT;
 		return;
@@ -232,10 +232,10 @@ HAL_StatusTypeDef Downstream_TransmitPacket(DownstreamPacketTypeDef* packetToWri
 		DownstreamInterfaceState = DOWNSTREAM_INTERFACE_TX_SIZE_WAIT;
 		CurrentWorkingPacket = packetToWrite;
 
-		if (HAL_SPI_TransmitReceive_IT(&Hspi1,
-									   (uint8_t*)&CurrentWorkingPacket->Length16,
-									   (uint8_t*)&TemporaryIncomingPacketLength,
-									   2) != HAL_OK)		//We only need to write one word, but the peripheral library freaks out...
+		if (HAL_SPI_TransmitReceive_DMA(&Hspi1,
+									    (uint8_t*)&CurrentWorkingPacket->Length16,
+									    (uint8_t*)&TemporaryIncomingPacketLength,
+									    2) != HAL_OK)		//We only need to write one word, but the peripheral library freaks out...
 		{
 			DOWNSTREAM_SPI_FREAKOUT;
 			return HAL_ERROR;
@@ -274,7 +274,7 @@ void Downstream_SPIProcess(void)
 	//Finished transmitting packet size
 	if (DownstreamInterfaceState == DOWNSTREAM_INTERFACE_TX_SIZE_WAIT)
 	{
-		if (TemporaryIncomingPacketLength != 0)
+		if ((uint16_t)TemporaryIncomingPacketLength != 0)
 		{
 			//Currently we just freak out if Upstream sends us an unexpected command.
 			//Theoretically we could reset our downstream state machine and accept the new command...
@@ -283,10 +283,10 @@ void Downstream_SPIProcess(void)
 		}
 
 		DownstreamInterfaceState = DOWNSTREAM_INTERFACE_TX_PACKET_WAIT;
-		if (HAL_SPI_TransmitReceive_IT(&Hspi1,
-									   &CurrentWorkingPacket->CommandClass,
-									   &CurrentWorkingPacket->CommandClass,
-									   ((CurrentWorkingPacket->Length16 < 2) ? 2 : CurrentWorkingPacket->Length16)) != HAL_OK)
+		if (HAL_SPI_TransmitReceive_DMA(&Hspi1,
+									    &CurrentWorkingPacket->CommandClass,
+									    &CurrentWorkingPacket->CommandClass,
+									    ((CurrentWorkingPacket->Length16 < 2) ? 2 : CurrentWorkingPacket->Length16)) != HAL_OK)
 		{
 			DOWNSTREAM_SPI_FREAKOUT;
 			return;
@@ -306,10 +306,10 @@ void Downstream_SPIProcess(void)
 			DownstreamInterfaceState = DOWNSTREAM_INTERFACE_TX_SIZE_WAIT;
 			CurrentWorkingPacket = NextTxPacket;
 			NextTxPacket = NULL;
-			if (HAL_SPI_TransmitReceive_IT(&Hspi1,
-										   (uint8_t*)&CurrentWorkingPacket->Length16,
-										   (uint8_t*)&TemporaryIncomingPacketLength,
-										   2) != HAL_OK)		//We only need to write one word, but the peripheral library freaks out...
+			if (HAL_SPI_TransmitReceive_DMA(&Hspi1,
+										    (uint8_t*)&CurrentWorkingPacket->Length16,
+										    (uint8_t*)&TemporaryIncomingPacketLength,
+										    2) != HAL_OK)		//We only need to write one word, but the peripheral library freaks out...
 			{
 				DOWNSTREAM_SPI_FREAKOUT;
 				return;
@@ -336,10 +336,10 @@ void Downstream_SPIProcess(void)
 			return;
 		}
 		DownstreamInterfaceState = DOWNSTREAM_INTERFACE_RX_PACKET_WAIT;
-		if (HAL_SPI_TransmitReceive_IT(&Hspi1,
-									   &CurrentWorkingPacket->CommandClass,
-									   &CurrentWorkingPacket->CommandClass,
-									   ((CurrentWorkingPacket->Length16 < 2) ? 2 : CurrentWorkingPacket->Length16)) != HAL_OK)
+		if (HAL_SPI_TransmitReceive_DMA(&Hspi1,
+									    &CurrentWorkingPacket->CommandClass,
+									    &CurrentWorkingPacket->CommandClass,
+									    ((CurrentWorkingPacket->Length16 < 2) ? 2 : CurrentWorkingPacket->Length16)) != HAL_OK)
 		{
 			DOWNSTREAM_SPI_FREAKOUT;
 			return;
diff --git a/Downstream/Src/hal_msp.c b/Downstream/Src/hal_msp.c
index 4bc59d3..157391e 100644
--- a/Downstream/Src/hal_msp.c
+++ b/Downstream/Src/hal_msp.c
@@ -59,7 +59,7 @@ void HAL_SPI_MspInit(SPI_HandleTypeDef* hspi)
   if(hspi->Instance==SPI1)
   {
     __SPI1_CLK_ENABLE();
-//    __DMA2_CLK_ENABLE();
+    __DMA2_CLK_ENABLE();
   
     /**SPI1 GPIO Configuration
     PA4     ------> SPI_NSS
@@ -84,9 +84,39 @@ void HAL_SPI_MspInit(SPI_HandleTypeDef* hspi)
     GPIO_InitStruct.Pull = GPIO_NOPULL;
     HAL_GPIO_Init(UPSTREAM_TX_REQUEST_PORT, &GPIO_InitStruct);
 
-    //Interrupt-based SPI now!
-    HAL_NVIC_SetPriority(SPI1_IRQn, INT_PRIORITY_SPI, 0);
-    HAL_NVIC_EnableIRQ(SPI1_IRQn);
+    /* Peripheral DMA init*/
+    hdma_spi1_rx.Instance = DMA2_Stream2;
+    hdma_spi1_rx.Init.Channel = DMA_CHANNEL_3;
+    hdma_spi1_rx.Init.Direction = DMA_PERIPH_TO_MEMORY;
+    hdma_spi1_rx.Init.PeriphInc = DMA_PINC_DISABLE;
+    hdma_spi1_rx.Init.MemInc = DMA_MINC_ENABLE;
+    hdma_spi1_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;
+    hdma_spi1_rx.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD;
+    hdma_spi1_rx.Init.Mode = DMA_NORMAL;
+    hdma_spi1_rx.Init.Priority = DMA_PRIORITY_MEDIUM;
+    hdma_spi1_rx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
+    HAL_DMA_Init(&hdma_spi1_rx);
+    __HAL_LINKDMA(hspi,hdmarx,hdma_spi1_rx);
+
+    hdma_spi1_tx.Instance = DMA2_Stream3;
+    hdma_spi1_tx.Init.Channel = DMA_CHANNEL_3;
+    hdma_spi1_tx.Init.Direction = DMA_MEMORY_TO_PERIPH;
+    hdma_spi1_tx.Init.PeriphInc = DMA_PINC_DISABLE;
+    hdma_spi1_tx.Init.MemInc = DMA_MINC_ENABLE;
+    hdma_spi1_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;
+    hdma_spi1_tx.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD;
+    hdma_spi1_tx.Init.Mode = DMA_NORMAL;
+    hdma_spi1_tx.Init.Priority = DMA_PRIORITY_MEDIUM;
+    hdma_spi1_tx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
+    HAL_DMA_Init(&hdma_spi1_tx);
+    __HAL_LINKDMA(hspi,hdmatx,hdma_spi1_tx);
+
+    /* DMA interrupt init */
+    HAL_NVIC_SetPriority(DMA2_Stream2_IRQn, INT_PRIORITY_SPI_DMA, 0);
+    HAL_NVIC_EnableIRQ(DMA2_Stream2_IRQn);
+    HAL_NVIC_SetPriority(DMA2_Stream3_IRQn, INT_PRIORITY_SPI_DMA, 0);
+    HAL_NVIC_EnableIRQ(DMA2_Stream3_IRQn);
+
   }
 }
 
@@ -104,6 +134,10 @@ void HAL_SPI_MspDeInit(SPI_HandleTypeDef* hspi)
     PA7     ------> SPI1_MOSI 
     */
     HAL_GPIO_DeInit(GPIOA, GPIO_PIN_5|GPIO_PIN_6|GPIO_PIN_7);
+
+    /* Peripheral DMA DeInit*/
+    HAL_DMA_DeInit(hspi->hdmarx);
+    HAL_DMA_DeInit(hspi->hdmatx);
   }
 
 }
diff --git a/Downstream/Src/interrupts.c b/Downstream/Src/interrupts.c
index 411f8ba..15e0f01 100644
--- a/Downstream/Src/interrupts.c
+++ b/Downstream/Src/interrupts.c
@@ -43,10 +43,8 @@
 
 /* External variables --------------------------------------------------------*/
 extern HCD_HandleTypeDef hhcd_USB_OTG_FS;
-extern SPI_HandleTypeDef Hspi1;
-
-//extern DMA_HandleTypeDef hdma_spi1_rx;
-//extern DMA_HandleTypeDef hdma_spi1_tx;
+extern DMA_HandleTypeDef hdma_spi1_rx;
+extern DMA_HandleTypeDef hdma_spi1_tx;
 
 /******************************************************************************/
 /*            Cortex-M4 Processor Interruption and Exception Handlers         */ 
@@ -69,17 +67,26 @@ void SysTick_Handler(void)
 /******************************************************************************/
 
 
-void SPI1_IRQHandler(void)
+
+void DMA2_Stream2_IRQHandler(void)
 {
-	SPI_INT_ACTIVE_ON;
-	HAL_SPI_IRQHandler(&Hspi1);
-	SPI_INT_ACTIVE_OFF;
+  //SPI_INT_ACTIVE_ON;
+  HAL_DMA_IRQHandler(&hdma_spi1_rx);
+  //SPI_INT_ACTIVE_OFF;
 }
 
+void DMA2_Stream3_IRQHandler(void)
+{
+  //SPI_INT_ACTIVE_ON;
+  HAL_DMA_IRQHandler(&hdma_spi1_tx);
+  //SPI_INT_ACTIVE_OFF;
+}
 
 void OTG_FS_IRQHandler(void)
 {
-  HAL_HCD_IRQHandler(&hhcd_USB_OTG_FS);
+	SPI_INT_ACTIVE_ON;
+	HAL_HCD_IRQHandler(&hhcd_USB_OTG_FS);
+	SPI_INT_ACTIVE_OFF;
 }
 
 
diff --git a/Downstream/Src/usbh_config.c b/Downstream/Src/usbh_config.c
index cf23d88..2421772 100644
--- a/Downstream/Src/usbh_config.c
+++ b/Downstream/Src/usbh_config.c
@@ -67,7 +67,7 @@ void HAL_HCD_MspInit(HCD_HandleTypeDef* hhcd)
     __USB_OTG_FS_CLK_ENABLE();
 
     /* Peripheral interrupt init*/
-    HAL_NVIC_SetPriority(OTG_FS_IRQn, INT_PRIORITY_OTG_FS, 0);
+    HAL_NVIC_SetPriority(OTG_FS_IRQn, INT_PRIORITY_USB, 0);
     HAL_NVIC_EnableIRQ(OTG_FS_IRQn);
   }
 }
diff --git a/Upstream/Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_dma.c b/Upstream/Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_dma.c
index a965390..c95e23d 100755
--- a/Upstream/Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_dma.c
+++ b/Upstream/Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_dma.c
@@ -408,7 +408,7 @@ HAL_StatusTypeDef HAL_DMA_Start_IT(DMA_HandleTypeDef *hdma, uint32_t SrcAddress,
   __HAL_DMA_ENABLE_IT(hdma, DMA_IT_TC);
 
   /* Enable the Half transfer complete interrupt */
-  __HAL_DMA_ENABLE_IT(hdma, DMA_IT_HT);  
+//  __HAL_DMA_ENABLE_IT(hdma, DMA_IT_HT);
 
   /* Enable the transfer Error interrupt */
   __HAL_DMA_ENABLE_IT(hdma, DMA_IT_TE);
diff --git a/Upstream/Inc/board_config.h b/Upstream/Inc/board_config.h
index b4fc59d..e576c57 100644
--- a/Upstream/Inc/board_config.h
+++ b/Upstream/Inc/board_config.h
@@ -34,10 +34,10 @@
 #define FAULT_LED_ON			STAT_LED_ON
 #define FAULT_LED_OFF			STAT_LED_OFF
 
-#define SPI_INT_ACTIVE_PIN		GPIO_PIN_5		/////////Temporary indicator of SPI activity
-#define SPI_INT_ACTIVE_PORT		GPIOB
-#define SPI_INT_ACTIVE_ON		SPI_INT_ACTIVE_PORT->BSRR = (SPI_INT_ACTIVE_PIN << BSRR_SHIFT_HIGH)
-#define SPI_INT_ACTIVE_OFF		SPI_INT_ACTIVE_PORT->BSRR = (SPI_INT_ACTIVE_PIN << BSRR_SHIFT_LOW)
+#define INT_ACTIVE_PIN			GPIO_PIN_5		/////////Temporary indicator of SPI activity
+#define INT_ACTIVE_PORT			GPIOB
+#define INT_ACTIVE_ON			INT_ACTIVE_PORT->BSRR = (INT_ACTIVE_PIN << BSRR_SHIFT_HIGH)
+#define INT_ACTIVE_OFF			INT_ACTIVE_PORT->BSRR = (INT_ACTIVE_PIN << BSRR_SHIFT_LOW)
 
 #define SPI1_NSS_PIN			GPIO_PIN_4
 #define SPI1_NSS_PORT			GPIOA
diff --git a/Upstream/Inc/interrupts.h b/Upstream/Inc/interrupts.h
index 1946eae..eace701 100755
--- a/Upstream/Inc/interrupts.h
+++ b/Upstream/Inc/interrupts.h
@@ -51,9 +51,9 @@
 *         A lower priority value indicates a higher priority. */
 
 #define INT_PRIORITY_SYSTICK	2
-#define INT_PRIORITY_SPI		8			//SPI is more important than USB now!
-#define INT_PRIORITY_OTG_FS		10
-#define INT_PRIORITY_EXT3I		INT_PRIORITY_OTG_FS
+#define INT_PRIORITY_SPI_DMA	10			//SPI is more important than USB now!
+#define INT_PRIORITY_USB		10
+#define INT_PRIORITY_EXT3I		INT_PRIORITY_USB
 
 
 /* Exported macro ------------------------------------------------------------*/
@@ -61,8 +61,8 @@
 
 void OTG_FS_IRQHandler(void);
 void SysTick_Handler(void);
-//void DMA2_Stream2_IRQHandler(void);
-//void DMA2_Stream3_IRQHandler(void);
+void DMA2_Stream2_IRQHandler(void);
+void DMA2_Stream3_IRQHandler(void);
 void EXTI3_IRQHandler(void);
 
 
diff --git a/Upstream/Inc/upstream_spi.h b/Upstream/Inc/upstream_spi.h
index 73b1ef1..0bd610e 100644
--- a/Upstream/Inc/upstream_spi.h
+++ b/Upstream/Inc/upstream_spi.h
@@ -62,7 +62,7 @@ PacketBusyTypeDef;
 typedef struct
 {
 	PacketBusyTypeDef	Busy;						//Everything after Busy should be word-aligned
-	uint16_t			Length16 __ALIGN_END;			//Packet length includes CommandClass, Command, and Data
+	uint16_t			Length16 __ALIGN_END;		//Packet length includes CommandClass, Command, and Data
 	uint8_t				CommandClass;
 	uint8_t				Command;
 	uint8_t				Data[MSC_MEDIA_PACKET];		//Should (must?) be word-aligned, for USB copy routine
@@ -82,7 +82,6 @@ void Upstream_ReleasePacket(UpstreamPacketTypeDef* packetToRelease);
 HAL_StatusTypeDef Upstream_TransmitPacket(UpstreamPacketTypeDef* packetToWrite);
 HAL_StatusTypeDef Upstream_ReceivePacket(SpiPacketReceivedCallbackTypeDef callback);
 void Upstream_TxOkInterrupt(void);
-void Upstream_SPIProcess_InterruptSafe(void);
 void HAL_SPI_TxRxCpltCallback(SPI_HandleTypeDef *hspi);
 void HAL_SPI_ErrorCallback(SPI_HandleTypeDef *hspi);
 
diff --git a/Upstream/Src/hal_msp.c b/Upstream/Src/hal_msp.c
index bffb17d..d5da64f 100755
--- a/Upstream/Src/hal_msp.c
+++ b/Upstream/Src/hal_msp.c
@@ -41,8 +41,8 @@
 #include "board_config.h"
 
 
-//DMA_HandleTypeDef	spiTxDmaHandle;
-//DMA_HandleTypeDef	spiRxDmaHandle;
+DMA_HandleTypeDef	spiTxDmaHandle;
+DMA_HandleTypeDef	spiRxDmaHandle;
 
 
 /**
@@ -61,13 +61,12 @@ void HAL_MspInit(void)
 
 void HAL_SPI_MspInit(SPI_HandleTypeDef* hspi)
 {
-
   GPIO_InitTypeDef GPIO_InitStruct;
   if(hspi->Instance==SPI1)
   {
     /* Peripheral clock enable */
 	  __HAL_RCC_SPI1_CLK_ENABLE();
-//	  __HAL_RCC_DMA2_CLK_ENABLE();
+	  __HAL_RCC_DMA2_CLK_ENABLE();
 
     /**SPI1 GPIO Configuration    
     PA4     ------> GPIO manual slave select
@@ -96,9 +95,39 @@ void HAL_SPI_MspInit(SPI_HandleTypeDef* hspi)
 	HAL_NVIC_SetPriority(EXTI3_IRQn, INT_PRIORITY_EXT3I, 0);
 	HAL_NVIC_EnableIRQ(EXTI3_IRQn);
 
-	//Interrupt-based SPI now!
-	HAL_NVIC_SetPriority(SPI1_IRQn, INT_PRIORITY_SPI, 0);
-	HAL_NVIC_EnableIRQ(SPI1_IRQn);
+	//Prepare Tx DMA stream
+	hspi->hdmatx = &spiTxDmaHandle;
+	spiTxDmaHandle.Instance = DMA2_Stream3;
+	spiTxDmaHandle.Parent = hspi;
+	spiTxDmaHandle.Init.Channel = DMA_CHANNEL_3;
+	spiTxDmaHandle.Init.Direction = DMA_MEMORY_TO_PERIPH;
+	spiTxDmaHandle.Init.PeriphInc = DMA_PINC_DISABLE;
+	spiTxDmaHandle.Init.MemInc = DMA_MINC_ENABLE;
+	spiTxDmaHandle.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;
+	spiTxDmaHandle.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD;
+	spiTxDmaHandle.Init.Mode = DMA_NORMAL;
+	spiTxDmaHandle.Init.Priority = DMA_PRIORITY_MEDIUM;
+	spiTxDmaHandle.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
+	HAL_DMA_Init(&spiTxDmaHandle);
+	HAL_NVIC_SetPriority(DMA2_Stream3_IRQn, INT_PRIORITY_SPI_DMA, 0);
+	HAL_NVIC_EnableIRQ(DMA2_Stream3_IRQn);
+
+	//Prepare Rx DMA stream
+	hspi->hdmarx = &spiRxDmaHandle;
+	spiRxDmaHandle.Instance = DMA2_Stream2;
+	spiRxDmaHandle.Parent = hspi;
+	spiRxDmaHandle.Init.Channel = DMA_CHANNEL_3;
+	spiRxDmaHandle.Init.Direction = DMA_PERIPH_TO_MEMORY;
+	spiRxDmaHandle.Init.PeriphInc = DMA_PINC_DISABLE;
+	spiRxDmaHandle.Init.MemInc = DMA_MINC_ENABLE;
+	spiRxDmaHandle.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;
+	spiRxDmaHandle.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD;
+	spiRxDmaHandle.Init.Mode = DMA_NORMAL;
+	spiRxDmaHandle.Init.Priority = DMA_PRIORITY_MEDIUM;
+	spiRxDmaHandle.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
+	HAL_DMA_Init(&spiRxDmaHandle);
+	HAL_NVIC_SetPriority(DMA2_Stream2_IRQn, INT_PRIORITY_SPI_DMA, 0);
+	HAL_NVIC_EnableIRQ(DMA2_Stream2_IRQn);
   }
 }
 
@@ -109,7 +138,7 @@ void HAL_SPI_MspDeInit(SPI_HandleTypeDef* hspi)
   {
     /* Peripheral clock disable */
     __HAL_RCC_SPI1_CLK_DISABLE();
-//    __HAL_RCC_DMA2_CLK_DISABLE();
+    __HAL_RCC_DMA2_CLK_DISABLE();
   
     /**SPI1 GPIO Configuration    
     PA4     ------> SPI1_NSS
@@ -118,6 +147,11 @@ void HAL_SPI_MspDeInit(SPI_HandleTypeDef* hspi)
     PA7     ------> SPI1_MOSI 
     */
     HAL_GPIO_DeInit(GPIOA, GPIO_PIN_5|GPIO_PIN_6|GPIO_PIN_7);
+    HAL_DMA_DeInit(&spiTxDmaHandle);
+	HAL_DMA_DeInit(&spiRxDmaHandle);
+
+	HAL_NVIC_DisableIRQ(DMA2_Stream3_IRQn);
+	HAL_NVIC_DisableIRQ(DMA2_Stream2_IRQn);
   }
 
 }
diff --git a/Upstream/Src/interrupts.c b/Upstream/Src/interrupts.c
index 2b7ad36..d950891 100755
--- a/Upstream/Src/interrupts.c
+++ b/Upstream/Src/interrupts.c
@@ -48,10 +48,8 @@
 /* External variables --------------------------------------------------------*/
 
 extern PCD_HandleTypeDef	hpcd_USB_OTG_FS;
-extern SPI_HandleTypeDef	Hspi1;
-
-//extern DMA_HandleTypeDef	spiTxDmaHandle;
-//extern DMA_HandleTypeDef	spiRxDmaHandle;
+extern DMA_HandleTypeDef	spiTxDmaHandle;
+extern DMA_HandleTypeDef	spiRxDmaHandle;
 
 
 /******************************************************************************/
@@ -74,6 +72,20 @@ void OTG_FS_IRQHandler(void)
 	HAL_PCD_IRQHandler(&hpcd_USB_OTG_FS);
 }
 
+void DMA2_Stream2_IRQHandler(void)
+{
+	INT_ACTIVE_ON;
+	HAL_DMA_IRQHandler(&spiRxDmaHandle);
+	INT_ACTIVE_OFF;
+}
+
+void DMA2_Stream3_IRQHandler(void)
+{
+	INT_ACTIVE_ON;
+	HAL_DMA_IRQHandler(&spiTxDmaHandle);
+	INT_ACTIVE_OFF;
+}
+
 void EXTI3_IRQHandler(void)
 {
 	__HAL_GPIO_EXTI_CLEAR_IT(DOWNSTREAM_TX_OK_PIN);
@@ -83,14 +95,5 @@ void EXTI3_IRQHandler(void)
 /////////////////////////
 
 
-//As SPI DMA doesn't work when the USB peripheral is active,
-//we are forced to use interrupts. This must be higher priority than USB.
-void SPI1_IRQHandler(void)
-{
-	SPI_INT_ACTIVE_ON;
-	HAL_SPI_IRQHandler(&Hspi1);
-	SPI_INT_ACTIVE_OFF;
-}
-
 
 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
diff --git a/Upstream/Src/main.c b/Upstream/Src/main.c
index 1d2a9fd..5342664 100755
--- a/Upstream/Src/main.c
+++ b/Upstream/Src/main.c
@@ -71,7 +71,7 @@ int main(void)
 
   while (1)
   {
-	  Upstream_SPIProcess_InterruptSafe();
+  
   }
 }
 
@@ -156,11 +156,11 @@ void GPIO_Init(void)
 	STAT_LED_OFF;
 
 	//SPI_INT_ACTIVE indicator
-	GPIO_InitStruct.Pin = SPI_INT_ACTIVE_PIN;
+	GPIO_InitStruct.Pin = INT_ACTIVE_PIN;
 	//GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
 	//GPIO_InitStruct.Pull = GPIO_NOPULL;
-	HAL_GPIO_Init(SPI_INT_ACTIVE_PORT, &GPIO_InitStruct);
-	SPI_INT_ACTIVE_OFF;
+	HAL_GPIO_Init(INT_ACTIVE_PORT, &GPIO_InitStruct);
+	INT_ACTIVE_OFF;
 }
 
 /* USER CODE BEGIN 4 */
diff --git a/Upstream/Src/upstream_spi.c b/Upstream/Src/upstream_spi.c
index b6aff2f..e318075 100644
--- a/Upstream/Src/upstream_spi.c
+++ b/Upstream/Src/upstream_spi.c
@@ -31,7 +31,6 @@ SpiPacketReceivedCallbackTypeDef	ReceivePacketCallback		= NULL;	//Indicates some
 
 uint32_t					TemporaryIncomingPacketLength;		//We don't actually care about what Downstream sends us when we are transmitting. We just need somewhere to put it so that our own packet length is not overwritten.
 uint8_t						TxOkInterruptReceived = 0;
-uint8_t						SpiInterruptCompleted = 0;
 uint8_t						SentCommandClass;
 uint8_t						SentCommand;
 
@@ -41,7 +40,6 @@ void Upstream_BeginTransmitPacketBody(void);
 HAL_StatusTypeDef Upstream_CheckBeginPacketReception(void);
 void Upstream_BeginReceivePacketSize(UpstreamPacketTypeDef* freePacket);
 void Upstream_BeginReceivePacketBody(void);
-void Upstream_SPIProcess(void);
 
 
 
@@ -58,7 +56,7 @@ void Upstream_InitSPI(void)
 	Hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
 	Hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
 	Hspi1.Init.NSS = SPI_NSS_SOFT;
-	Hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_8;	//42MHz APB2 / 32 = 1.3Mbaud
+	Hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_4;	//42MHz APB2 / 4 = 10.5Mbaud
 	Hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
 	Hspi1.Init.TIMode = SPI_TIMODE_DISABLED;
 	Hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_ENABLED;
@@ -231,37 +229,6 @@ HAL_StatusTypeDef Upstream_TransmitPacket(UpstreamPacketTypeDef* packetToWrite)
 //at SPI1 interrupt priority. Assume *hspi points to our hspi1.
 //We TxRx our outgoing packet because the SPI hardware freaks out if we only Tx it :-/
 void HAL_SPI_TxRxCpltCallback(SPI_HandleTypeDef *hspi)
-{
-	SpiInterruptCompleted = 1;
-
-	//Elevate priority here to stop EXT3I sneaking in
-	//before we have a chance to process UpstreamInterfaceState change.
-	__set_BASEPRI(INT_PRIORITY_OTG_FS << (8 - __NVIC_PRIO_BITS));
-}
-
-
-
-//Preemption protection wrapper around Upstream_SPIProcess()
-//We must protect against preemption by USB and EXT3 interrupts at priority 10!
-void Upstream_SPIProcess_InterruptSafe(void)
-{
-	//This is done on SPI interrupt callback...
-	//__set_BASEPRI(INT_PRIORITY_OTG_FS << (8 - __NVIC_PRIO_BITS));
-
-	if (SpiInterruptCompleted == 0)
-	{
-		return;
-	}
-	SpiInterruptCompleted = 0;
-	Upstream_SPIProcess();
-	__set_BASEPRI(0);
-}
-
-
-
-//Called from main().
-//Must be protected against preemption by USB and EXT3 interrupts at priority 10!
-void Upstream_SPIProcess(void)
 {
 	SpiPacketReceivedCallbackTypeDef tempPacketCallback;
 	UpstreamPacketTypeDef* tempPacketToFree;
@@ -475,10 +442,10 @@ void Upstream_BeginTransmitPacketSize(void)
 {
 	UpstreamInterfaceState = UPSTREAM_INTERFACE_TX_SIZE;
 	SPI1_NSS_ASSERT;
-	if (HAL_SPI_TransmitReceive_IT(&Hspi1,
-								   (uint8_t*)&CurrentWorkingPacket->Length16,
-								   (uint8_t*)&TemporaryIncomingPacketLength,
-								   2) != HAL_OK)		//We only need to write one word, but the peripheral library freaks out...
+	if (HAL_SPI_TransmitReceive_DMA(&Hspi1,
+									(uint8_t*)&CurrentWorkingPacket->Length16,
+									(uint8_t*)&TemporaryIncomingPacketLength,
+									2) != HAL_OK)		//We only need to write one word, but the peripheral library freaks out...
 	{
 		UPSTREAM_SPI_FREAKOUT;
 	}
@@ -490,10 +457,10 @@ void Upstream_BeginTransmitPacketBody(void)
 	UpstreamInterfaceState = UPSTREAM_INTERFACE_TX_PACKET;
 	SPI1_NSS_ASSERT;
 
-	if (HAL_SPI_TransmitReceive_IT(&Hspi1,
-								   &CurrentWorkingPacket->CommandClass,
-								   &CurrentWorkingPacket->CommandClass,
-								   ((CurrentWorkingPacket->Length16 < 2) ? 2 : CurrentWorkingPacket->Length16)) != HAL_OK)
+	if (HAL_SPI_TransmitReceive_DMA(&Hspi1,
+									&CurrentWorkingPacket->CommandClass,
+									&CurrentWorkingPacket->CommandClass,
+									((CurrentWorkingPacket->Length16 < 2) ? 2 : CurrentWorkingPacket->Length16)) != HAL_OK)
 	{
 		UPSTREAM_SPI_FREAKOUT;
 	}
@@ -516,13 +483,12 @@ void Upstream_BeginReceivePacketSize(UpstreamPacketTypeDef* freePacket)
 	}
 	UpstreamInterfaceState = UPSTREAM_INTERFACE_RX_SIZE;
 	CurrentWorkingPacket = freePacket;
-	CurrentWorkingPacket->Length16 = 0;		//Our RX buffer is used by HAL_SPI_Receive_DMA as dummy TX data, we set Length to 0 so downstream will know this is a dummy packet.
+	CurrentWorkingPacket->Length16 = 0;		//Our RX buffer is used by HAL_SPI_TransmitReceive_DMA as dummy TX data, we set Length to 0 so downstream will know this is a dummy packet.
 	SPI1_NSS_ASSERT;
-	TemporaryIncomingPacketLength = 0;
-	if (HAL_SPI_TransmitReceive_IT(&Hspi1,
-								   (uint8_t*)&TemporaryIncomingPacketLength,
-								   (uint8_t*)&CurrentWorkingPacket->Length16,
-								   2) != HAL_OK)		//We only need to write one word, but the peripheral library freaks out...
+	if (HAL_SPI_TransmitReceive_DMA(&Hspi1,
+									(uint8_t*)&CurrentWorkingPacket->Length16,
+									(uint8_t*)&CurrentWorkingPacket->Length16,
+									2) != HAL_OK)		//We only need to write one word, but the peripheral library freaks out...
 	{
 		UPSTREAM_SPI_FREAKOUT;
 	}
@@ -533,10 +499,10 @@ void Upstream_BeginReceivePacketBody(void)
 {
 	UpstreamInterfaceState = UPSTREAM_INTERFACE_RX_PACKET;
 	SPI1_NSS_ASSERT;
-	if (HAL_SPI_TransmitReceive_IT(&Hspi1,
-								   &CurrentWorkingPacket->CommandClass,
-								   &CurrentWorkingPacket->CommandClass,
-								   ((CurrentWorkingPacket->Length16 < 2) ? 2 : CurrentWorkingPacket->Length16)) != HAL_OK)
+	if (HAL_SPI_TransmitReceive_DMA(&Hspi1,
+									&CurrentWorkingPacket->CommandClass,
+									&CurrentWorkingPacket->CommandClass,
+									((CurrentWorkingPacket->Length16 < 2) ? 2 : CurrentWorkingPacket->Length16)) != HAL_OK)
 	{
 		UPSTREAM_SPI_FREAKOUT;
 	}
diff --git a/Upstream/Src/usbd_config.c b/Upstream/Src/usbd_config.c
index efe7bd1..79d9132 100755
--- a/Upstream/Src/usbd_config.c
+++ b/Upstream/Src/usbd_config.c
@@ -79,7 +79,7 @@ void HAL_PCD_MspInit(PCD_HandleTypeDef* hpcd)
     GPIO_InitStruct.Alternate = GPIO_AF10_OTG_FS;
     HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
 
-    HAL_NVIC_SetPriority(OTG_FS_IRQn, INT_PRIORITY_OTG_FS, 0);
+    HAL_NVIC_SetPriority(OTG_FS_IRQn, INT_PRIORITY_USB, 0);
     HAL_NVIC_EnableIRQ(OTG_FS_IRQn);
   /* USER CODE BEGIN USB_OTG_FS_MspInit 1 */