diff --git a/Downstream/Inc/board_config.h b/Downstream/Inc/board_config.h
index f34e573..6b45bd5 100644
--- a/Downstream/Inc/board_config.h
+++ b/Downstream/Inc/board_config.h
@@ -35,20 +35,18 @@
 #define USB_HS_VBUSON_PIN		GPIO_PIN_8
 #define USB_HS_VBUSON_PORT		GPIOA
 
-#define STAT_LED_PIN			GPIO_PIN_13
-#define STAT_LED_PORT			GPIOC
-#define STAT_LED_ON				(STAT_LED_PORT->BSRR = (STAT_LED_PIN << BSRR_SHIFT_LOW))	//Stat LED is active-low
-#define STAT_LED_OFF			(STAT_LED_PORT->BSRR = (STAT_LED_PIN << BSRR_SHIFT_HIGH))
+#define FAULT_LED_PIN			GPIO_PIN_13
+#define FAULT_LED_PORT			GPIOC
+#define FAULT_LED_ON			(FAULT_LED_PORT->BSRR = (FAULT_LED_PIN << BSRR_SHIFT_LOW))	//Fault LED is active-low
+#define FAULT_LED_OFF			(FAULT_LED_PORT->BSRR = (FAULT_LED_PIN << BSRR_SHIFT_HIGH))
 
-//#define RUN_LED_ON......
-#define FAULT_LED_ON			STAT_LED_ON
-#define FAULT_LED_OFF			STAT_LED_OFF
+#define H405_FAULT_LED_PIN		GPIO_PIN_12		//Fault LED on Olimex H405 board
+#define H405_FAULT_LED_ON		(FAULT_LED_PORT->BSRR = (H405_FAULT_LED_PIN << BSRR_SHIFT_LOW))
 
-
-#define SPI_INT_ACTIVE_PIN		GPIO_PIN_2		/////////Temporary indicator of SPI activity
-#define SPI_INT_ACTIVE_PORT		GPIOA
-#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_2		//Temporary indicator of SPI (or whatever) activity
+#define INT_ACTIVE_PORT			GPIOA
+#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
@@ -58,5 +56,7 @@
 #define UPSTREAM_TX_REQUEST_ASSERT		(UPSTREAM_TX_REQUEST_PORT->BSRR = (UPSTREAM_TX_REQUEST_PIN << BSRR_SHIFT_LOW))
 #define UPSTREAM_TX_REQUEST_DEASSERT	(UPSTREAM_TX_REQUEST_PORT->BSRR = (UPSTREAM_TX_REQUEST_PIN << BSRR_SHIFT_HIGH))
 
+#define DBGMCU_IDCODE_DEV_ID_405_407_415_417	0x413
+
 
 #endif /* INC_BOARD_CONFIG_H_ */
diff --git a/Downstream/Src/interrupts.c b/Downstream/Src/interrupts.c
index 15e0f01..bc0cebe 100644
--- a/Downstream/Src/interrupts.c
+++ b/Downstream/Src/interrupts.c
@@ -84,9 +84,9 @@ void DMA2_Stream3_IRQHandler(void)
 
 void OTG_FS_IRQHandler(void)
 {
-	SPI_INT_ACTIVE_ON;
+	INT_ACTIVE_ON;
 	HAL_HCD_IRQHandler(&hhcd_USB_OTG_FS);
-	SPI_INT_ACTIVE_OFF;
+	INT_ACTIVE_OFF;
 }
 
 
diff --git a/Downstream/Src/main.c b/Downstream/Src/main.c
index cedded5..b480514 100644
--- a/Downstream/Src/main.c
+++ b/Downstream/Src/main.c
@@ -45,11 +45,16 @@
 /* Private function prototypes -----------------------------------------------*/
 void SystemClock_Config(void);
 static void GPIO_Init(void);
+void CheckFirmwareMatchesHardware(void);
 
 
 
 int main(void)
 {
+	//First things first!
+	CheckFirmwareMatchesHardware();
+
+
 	/* Configure the system clock */
 	SystemClock_Config();
 
@@ -71,6 +76,45 @@ int main(void)
 }
 
 
+void CheckFirmwareMatchesHardware(void)
+{
+	//Check we are running on the expected hardware:
+	//STM32F407 on an Olimex dev board
+
+	GPIO_InitTypeDef GPIO_InitStruct;
+
+	if ((*(uint32_t*)DBGMCU_BASE & DBGMCU_IDCODE_DEV_ID) == DBGMCU_IDCODE_DEV_ID_405_407_415_417)
+	{
+		//The H407 board has a STAT LED on PC13. If there is no pullup on this pin,
+		//then we are probably running on another board.
+		__HAL_RCC_GPIOC_CLK_ENABLE();
+		GPIO_InitStruct.Pin = FAULT_LED_PIN;
+		GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
+		GPIO_InitStruct.Pull = GPIO_PULLDOWN;
+		GPIO_InitStruct.Speed = GPIO_SPEED_LOW;
+		GPIO_InitStruct.Alternate = 0;
+		HAL_GPIO_Init(FAULT_LED_PORT, &GPIO_InitStruct);
+		GPIO_InitStruct.Pull = GPIO_NOPULL;
+		HAL_GPIO_Init(FAULT_LED_PORT, &GPIO_InitStruct);
+
+		if (FAULT_LED_PORT->IDR & FAULT_LED_PIN)
+		{
+			//Pin pulls up, so this is an H407 board :)
+			return;
+		}
+	}
+
+	//This is not the hardware we expected, so turn on our fault LED(s) and die in a heap.
+	GPIO_InitStruct.Pin = FAULT_LED_PIN | H405_FAULT_LED_PIN;
+	GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
+	GPIO_InitStruct.Pull = GPIO_NOPULL;
+	HAL_GPIO_Init(FAULT_LED_PORT, &GPIO_InitStruct);
+	FAULT_LED_ON;
+	H405_FAULT_LED_ON;
+	while (1);
+}
+
+
 /** System Clock Configuration
 */
 void SystemClock_Config(void)
@@ -158,14 +202,14 @@ void GPIO_Init(void)
 	HAL_GPIO_Init(USB_HS_VBUSON_PORT, &GPIO_InitStruct);
 
 	//STAT_LED is output
-	STAT_LED_OFF;
-	GPIO_InitStruct.Pin = STAT_LED_PIN;
-	HAL_GPIO_Init(STAT_LED_PORT, &GPIO_InitStruct);
+	FAULT_LED_OFF;
+	GPIO_InitStruct.Pin = FAULT_LED_PIN;
+	HAL_GPIO_Init(FAULT_LED_PORT, &GPIO_InitStruct);
 
 	//SPI_INT_ACTIVE indicator
-	GPIO_InitStruct.Pin = SPI_INT_ACTIVE_PIN;
-	HAL_GPIO_Init(SPI_INT_ACTIVE_PORT, &GPIO_InitStruct);
-	SPI_INT_ACTIVE_OFF;
+	GPIO_InitStruct.Pin = INT_ACTIVE_PIN;
+	HAL_GPIO_Init(INT_ACTIVE_PORT, &GPIO_InitStruct);
+	INT_ACTIVE_OFF;
 }
 
 
diff --git a/Upstream/Inc/board_config.h b/Upstream/Inc/board_config.h
index e576c57..e019ad7 100644
--- a/Upstream/Inc/board_config.h
+++ b/Upstream/Inc/board_config.h
@@ -25,16 +25,15 @@
 #define USB_P_PIN				GPIO_PIN_4
 #define USB_P_PORT				GPIOC
 
-#define STAT_LED_PIN			GPIO_PIN_12
-#define STAT_LED_PORT			GPIOC
-#define STAT_LED_ON				(STAT_LED_PORT->BSRR = (STAT_LED_PIN << BSRR_SHIFT_LOW))	//Stat LED is active-low
-#define STAT_LED_OFF			(STAT_LED_PORT->BSRR = (STAT_LED_PIN << BSRR_SHIFT_HIGH))
+#define FAULT_LED_PIN			GPIO_PIN_12
+#define FAULT_LED_PORT			GPIOC
+#define FAULT_LED_ON			(FAULT_LED_PORT->BSRR = (FAULT_LED_PIN << BSRR_SHIFT_LOW))	//Fault LED is active-low
+#define FAULT_LED_OFF			(FAULT_LED_PORT->BSRR = (FAULT_LED_PIN << BSRR_SHIFT_HIGH))
 
-//#define RUN_LED_ON......
-#define FAULT_LED_ON			STAT_LED_ON
-#define FAULT_LED_OFF			STAT_LED_OFF
+#define OTHER_BOARDS_FAULT_LED_PIN	GPIO_PIN_13		//Fault LED on Olimex H407 board, and USG v1.0
+#define OTHER_BOARDS_FAULT_LED_ON	(FAULT_LED_PORT->BSRR = (OTHER_BOARDS_FAULT_LED_PIN << BSRR_SHIFT_LOW))
 
-#define INT_ACTIVE_PIN			GPIO_PIN_5		/////////Temporary indicator of SPI activity
+#define INT_ACTIVE_PIN			GPIO_PIN_5			//Temporary indicator of SPI (or whatever) 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)
@@ -48,5 +47,7 @@
 #define DOWNSTREAM_TX_OK_PORT	GPIOA
 #define DOWNSTREAM_TX_OK_ACTIVE	(!(DOWNSTREAM_TX_OK_PORT->IDR & DOWNSTREAM_TX_OK_PIN))
 
+#define DBGMCU_IDCODE_DEV_ID_405_407_415_417	0x413
+
 
 #endif /* INC_BOARD_CONFIG_H_ */
diff --git a/Upstream/Src/main.c b/Upstream/Src/main.c
index 5342664..4c9ef98 100755
--- a/Upstream/Src/main.c
+++ b/Upstream/Src/main.c
@@ -50,32 +50,77 @@
 /* Private function prototypes -----------------------------------------------*/
 void SystemClock_Config(void);
 static void GPIO_Init(void);
+void CheckFirmwareMatchesHardware(void);
 
 
 
 int main(void)
 {
-  /* Configure the system clock */
-  SystemClock_Config();
+	//First things first!
+	CheckFirmwareMatchesHardware();
 
-  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
-  HAL_Init();
 
-  /* Initialize all configured peripherals */
-  GPIO_Init();
-  LED_Init();
-  USB_Device_Init();
+	/* Configure the system clock */
+	SystemClock_Config();
 
-  Upstream_InitStateMachine();
+	/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
+	HAL_Init();
 
+	/* Initialize all configured peripherals */
+	GPIO_Init();
+	LED_Init();
+	USB_Device_Init();
 
-  while (1)
-  {
-  
-  }
+	Upstream_InitStateMachine();
+
+
+	while (1)
+	{
+
+	}
 }
 
 
+void CheckFirmwareMatchesHardware(void)
+{
+	//Check we are running on the expected hardware:
+	//STM32F405 on an Olimex dev board
+
+	GPIO_InitTypeDef GPIO_InitStruct;
+
+	if ((*(uint32_t*)DBGMCU_BASE & DBGMCU_IDCODE_DEV_ID) == DBGMCU_IDCODE_DEV_ID_405_407_415_417)
+	{
+		//The H405 board has a STAT LED on PC12. If there is no pullup on this pin,
+		//then we are probably running on another board.
+		__HAL_RCC_GPIOC_CLK_ENABLE();
+		GPIO_InitStruct.Pin = FAULT_LED_PIN;
+		GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
+		GPIO_InitStruct.Pull = GPIO_PULLDOWN;
+		GPIO_InitStruct.Speed = GPIO_SPEED_LOW;
+		GPIO_InitStruct.Alternate = 0;
+		HAL_GPIO_Init(FAULT_LED_PORT, &GPIO_InitStruct);
+		GPIO_InitStruct.Pull = GPIO_NOPULL;
+		HAL_GPIO_Init(FAULT_LED_PORT, &GPIO_InitStruct);
+
+		if (FAULT_LED_PORT->IDR & FAULT_LED_PIN)
+		{
+			//Pin pulls up, so this is an H405 board :)
+			return;
+		}
+	}
+
+	//This is not the hardware we expected, so turn on our fault LED(s) and die in a heap.
+	GPIO_InitStruct.Pin = FAULT_LED_PIN | OTHER_BOARDS_FAULT_LED_PIN;
+	GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
+	GPIO_InitStruct.Pull = GPIO_NOPULL;
+	HAL_GPIO_Init(FAULT_LED_PORT, &GPIO_InitStruct);
+	FAULT_LED_ON;
+	OTHER_BOARDS_FAULT_LED_ON;
+	while (1);
+}
+
+
+
 /** System Clock Configuration
 */
 void SystemClock_Config(void)
@@ -149,11 +194,11 @@ void GPIO_Init(void)
 	HAL_GPIO_Init(USB_P_PORT, &GPIO_InitStruct);
 
 	//STAT_LED is output
-	GPIO_InitStruct.Pin = STAT_LED_PIN;
+	GPIO_InitStruct.Pin = FAULT_LED_PIN;
 	GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
 	GPIO_InitStruct.Pull = GPIO_NOPULL;
-	HAL_GPIO_Init(STAT_LED_PORT, &GPIO_InitStruct);
-	STAT_LED_OFF;
+	HAL_GPIO_Init(FAULT_LED_PORT, &GPIO_InitStruct);
+	FAULT_LED_OFF;
 
 	//SPI_INT_ACTIVE indicator
 	GPIO_InitStruct.Pin = INT_ACTIVE_PIN;