diff --git a/flight/AHRS/pios_board.c b/flight/AHRS/pios_board.c
index cfe9c6d5f..7a6a61b21 100644
--- a/flight/AHRS/pios_board.c
+++ b/flight/AHRS/pios_board.c
@@ -301,8 +301,7 @@ const struct pios_i2c_adapter_cfg pios_i2c_main_adapter_cfg = {
 		  .flags = 0,	/* FIXME: check this */
 		  .init = {
 			   .NVIC_IRQChannel = I2C1_EV_IRQn,
-			   //.NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_HIGHEST,
-			   .NVIC_IRQChannelPreemptionPriority = 2,
+			   .NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_HIGHEST,
 			   .NVIC_IRQChannelSubPriority = 0,
 			   .NVIC_IRQChannelCmd = ENABLE,
 			   },
@@ -312,8 +311,7 @@ const struct pios_i2c_adapter_cfg pios_i2c_main_adapter_cfg = {
 		  .flags = 0,	/* FIXME: check this */
 		  .init = {
 			   .NVIC_IRQChannel = I2C1_ER_IRQn,
-			   //.NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_HIGHEST,
-			   .NVIC_IRQChannelPreemptionPriority = 2,
+			   .NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_HIGHEST,
 			   .NVIC_IRQChannelSubPriority = 0,
 			   .NVIC_IRQChannelCmd = ENABLE,
 			   },
diff --git a/flight/OpenPilot/System/pios_board.c b/flight/OpenPilot/System/pios_board.c
index f710b43a4..a6798003d 100644
--- a/flight/OpenPilot/System/pios_board.c
+++ b/flight/OpenPilot/System/pios_board.c
@@ -331,7 +331,7 @@ const struct pios_usart_cfg pios_usart_telem_cfg = {
     .handler = PIOS_USART_telem_irq_handler,
     .init    = {
       .NVIC_IRQChannel                   = USART2_IRQn,
-      .NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_HIGH,
+      .NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_MID,
       .NVIC_IRQChannelSubPriority        = 0,
       .NVIC_IRQChannelCmd                = ENABLE,
     },
@@ -378,7 +378,7 @@ const struct pios_usart_cfg pios_usart_gps_cfg = {
     .handler = PIOS_USART_gps_irq_handler,
     .init    = {
       .NVIC_IRQChannel                   = USART3_IRQn,
-      .NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_HIGH,
+      .NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_MID,
       .NVIC_IRQChannelSubPriority        = 0,
       .NVIC_IRQChannelCmd                = ENABLE,
     },
@@ -426,7 +426,7 @@ const struct pios_usart_cfg pios_usart_aux_cfg = {
     .handler = PIOS_USART_aux_irq_handler,
     .init    = {
       .NVIC_IRQChannel                   = USART1_IRQn,
-      .NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_HIGH,
+      .NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_MID,
       .NVIC_IRQChannelSubPriority        = 0,
       .NVIC_IRQChannelCmd                = ENABLE,
     },
diff --git a/flight/PiOS/Boards/STM3210E_OP.h b/flight/PiOS/Boards/STM3210E_OP.h
index e26731d01..5c17794b3 100644
--- a/flight/PiOS/Boards/STM3210E_OP.h
+++ b/flight/PiOS/Boards/STM3210E_OP.h
@@ -116,7 +116,7 @@ TIM8  | Servo 5   | Servo 6   | Servo 7   | Servo 8
 #define PIOS_BMP085_EOC_CLK                     RCC_APB2Periph_GPIOC
 #define PIOS_BMP085_EOC_EXTI_LINE               EXTI_Line15
 #define PIOS_BMP085_EOC_IRQn                    EXTI15_10_IRQn
-#define PIOS_BMP085_EOC_PRIO                    PIOS_IRQ_PRIO_HIGH
+#define PIOS_BMP085_EOC_PRIO                    PIOS_IRQ_PRIO_LOW
 //#define PIOS_BMP085_OVERSAMPLING                2
 #define PIOS_BMP085_OVERSAMPLING                3
 
@@ -353,7 +353,7 @@ TIM8  | Servo 5   | Servo 6   | Servo 7   | Servo 8
                                                 /* With an ADCCLK = 14 MHz and a sampling time of 293.5 cycles: */
                                                 /* Tconv = 239.5 + 12.5 = 252 cycles = 18?s */
                                                 /* (1 / (ADCCLK / CYCLES)) = Sample Time (?S) */
-#define PIOS_ADC_IRQ_PRIO                       PIOS_IRQ_PRIO_HIGH
+#define PIOS_ADC_IRQ_PRIO                       PIOS_IRQ_PRIO_MID
 
 //-------------------------
 // GPIO
diff --git a/flight/PiOS/STM32F10x/pios_ppm.c b/flight/PiOS/STM32F10x/pios_ppm.c
index cb3e08cfc..107da6ba0 100644
--- a/flight/PiOS/STM32F10x/pios_ppm.c
+++ b/flight/PiOS/STM32F10x/pios_ppm.c
@@ -68,8 +68,8 @@ void PIOS_PPM_Init(void)
 
 	/* Enable timer interrupts */
 	NVIC_InitTypeDef NVIC_InitStructure;
-	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
-	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
+	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_MID;
+	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
 	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
 	NVIC_InitStructure.NVIC_IRQChannel = PIOS_PPM_TIM_IRQ;
 	NVIC_Init(&NVIC_InitStructure);
@@ -120,8 +120,8 @@ void PIOS_PPM_Init(void)
 
 	/* Configure interrupts */
 	NVIC_InitStructure.NVIC_IRQChannel = PIOS_PPM_SUPV_IRQ_CHANNEL;
-	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
-	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
+	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_MID;
+	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
 	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
 	NVIC_Init(&NVIC_InitStructure);
 
diff --git a/flight/PiOS/STM32F10x/pios_pwm.c b/flight/PiOS/STM32F10x/pios_pwm.c
index 412466dd5..e8cdeecb1 100644
--- a/flight/PiOS/STM32F10x/pios_pwm.c
+++ b/flight/PiOS/STM32F10x/pios_pwm.c
@@ -79,8 +79,8 @@ void PIOS_PWM_Init(void)
 
 	/* Enable timer interrupts */
 	NVIC_InitTypeDef NVIC_InitStructure;
-	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
-	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
+	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_MID;
+	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
 	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
 	for (i = 0; i < PIOS_PWM_NUM_TIMS; i++) {
 		NVIC_InitStructure.NVIC_IRQChannel = PIOS_PWM_TIM_IRQ[i];
@@ -144,8 +144,8 @@ void PIOS_PWM_Init(void)
 
 	/* Configure interrupts */
 	NVIC_InitStructure.NVIC_IRQChannel = PIOS_PWM_SUPV_IRQ_CHANNEL;
-	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
-	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
+	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_MID;
+	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
 	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
 	NVIC_Init(&NVIC_InitStructure);
 
diff --git a/flight/PiOS/STM32F10x/pios_spektrum.c b/flight/PiOS/STM32F10x/pios_spektrum.c
index 675a50fb4..8f49b8941 100644
--- a/flight/PiOS/STM32F10x/pios_spektrum.c
+++ b/flight/PiOS/STM32F10x/pios_spektrum.c
@@ -66,8 +66,8 @@ void PIOS_SPEKTRUM_Init(void)
 
 	/* Configure interrupts */
 	NVIC_InitStructure.NVIC_IRQChannel = PIOS_SPEKTRUM_SUPV_IRQ_CHANNEL;
-	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
-	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
+	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_MID;
+	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
 	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
 	NVIC_Init(&NVIC_InitStructure);
 
diff --git a/flight/PiOS/STM32F10x/pios_usb_hid.c b/flight/PiOS/STM32F10x/pios_usb_hid.c
index fbd6f5e3c..5fb49900a 100644
--- a/flight/PiOS/STM32F10x/pios_usb_hid.c
+++ b/flight/PiOS/STM32F10x/pios_usb_hid.c
@@ -96,7 +96,6 @@ int32_t PIOS_USB_HID_Init(uint32_t mode)
 	/* Enable the USB Interrupts */
 	/* 2 bit for pre-emption priority, 2 bits for subpriority */
 	NVIC_InitTypeDef NVIC_InitStructure;
-	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
 	NVIC_InitStructure.NVIC_IRQChannel = USB_LP_CAN1_RX0_IRQn;
 	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_LOW;
 	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;