diff --git a/include/arm11/gpio.h b/include/arm11/gpio.h
index ad88174..66feb29 100644
--- a/include/arm11/gpio.h
+++ b/include/arm11/gpio.h
@@ -10,7 +10,7 @@
  * @param[in]  reg     The register number.
  * @param[in]  bitNum  The bit number.
  */
-void gpioSetBit(u16 reg, u8 bitNum);
+void GPIO_setBit(u16 reg, u8 bitNum);
 
 /**
  * @brief      Clears a bit in the specified GPIO register.
@@ -18,4 +18,4 @@
  * @param[in]  reg     The register number.
  * @param[in]  bitNum  The bit number.
  */
-void gpioClearBit(u16 reg, u8 bitNum);
+void GPIO_clearBit(u16 reg, u8 bitNum);
diff --git a/include/arm11/interrupt.h b/include/arm11/interrupt.h
index 280d2c5..f2fbae9 100644
--- a/include/arm11/interrupt.h
+++ b/include/arm11/interrupt.h
@@ -5,26 +5,33 @@
 
 typedef enum
 {
-	IRQ_MPCORE_SW0  = 0,
-	IRQ_MPCORE_SW1  = 1,
-	IRQ_MPCORE_SW2  = 2,
-	IRQ_MPCORE_SW3  = 3,
-	IRQ_MPCORE_SW4  = 4,
-	IRQ_MPCORE_SW5  = 5,
-	IRQ_MPCORE_SW6  = 6,
-	IRQ_MPCORE_SW7  = 7,
-	IRQ_MPCORE_SW8  = 8,
-	IRQ_MPCORE_SW9  = 9,
-	IRQ_MPCORE_SW10 = 10,
-	IRQ_MPCORE_SW11 = 11,
-	IRQ_MPCORE_SW12 = 12,
-	IRQ_MPCORE_SW13 = 13,
-	IRQ_MPCORE_SW14 = 14,
-	IRQ_MPCORE_SW15 = 15,
-	IRQ_PDC0        = 42, // aka VBlank0
-	IRQ_PDC1        = 43, // aka VBlank1
-	IRQ_PXI_SYNC    = 80,
-	IRQ_MCU_HID     = 113
+	IRQ_MPCORE_SW0    = 0,
+	IRQ_MPCORE_SW1    = 1,
+	IRQ_MPCORE_SW2    = 2,
+	IRQ_MPCORE_SW3    = 3,
+	IRQ_MPCORE_SW4    = 4,
+	IRQ_MPCORE_SW5    = 5,
+	IRQ_MPCORE_SW6    = 6,
+	IRQ_MPCORE_SW7    = 7,
+	IRQ_MPCORE_SW8    = 8,
+	IRQ_MPCORE_SW9    = 9,
+	IRQ_MPCORE_SW10   = 10,
+	IRQ_MPCORE_SW11   = 11,
+	IRQ_MPCORE_SW12   = 12,
+	IRQ_MPCORE_SW13   = 13,
+	IRQ_MPCORE_SW14   = 14,
+	IRQ_MPCORE_SW15   = 15,
+	IRQ_PSC0          = 40, // Unconfirmed
+	IRQ_PSC1          = 41, // Unconfirmed
+	IRQ_PDC0          = 42, // aka VBlank0
+	IRQ_PDC1          = 43, // aka VBlank1
+	IRQ_PPF           = 44, // Unconfirmed
+	IRQ_P3D           = 45, // This is a guess
+	IRQ_PXI_SYNC      = 80,
+	IRQ_PXI_UNK       = 81, // Unknown what this is for
+	IRQ_PXI_NOT_FULL  = 82,
+	IRQ_PXI_NOT_EMPTY = 83,
+	IRQ_MCU_HID       = 113 // HOME/POWER button pressed/released
 } Interrupt;
 
 
@@ -69,15 +76,27 @@
 void softwareInterrupt(Interrupt id, u8 cpuMask);
 
 
-static inline void waitForIrq(void)
+static inline void waitForInterrupt(void)
 {
 	__asm__ __volatile__("wfi" : :);
 }
 
-/*inline u32 enterCriticalSection(void)
+static inline void enterCriticalSection(void)
 {
+	__asm__ __volatile__("cpsid i" : :);
 }
 
-inline void leaveCriticalSection(u32 oldState)
+static inline void leaveCriticalSection(void)
 {
-}*/
+	__asm__ __volatile__("cpsie i" : :);
+}
+
+static inline void waitForEvent(void)
+{
+	__asm__ __volatile__("wfe" : :);
+}
+
+static inline void signalEvent(void)
+{
+	__asm__ __volatile__("sev" : :);
+}
diff --git a/source/arm11/gpio.c b/source/arm11/gpio.c
index 416712c..cdc0442 100644
--- a/source/arm11/gpio.c
+++ b/source/arm11/gpio.c
@@ -6,12 +6,12 @@
 
 
 
-void gpioSetBit(u16 reg, u8 bitNum)
+void GPIO_setBit(u16 reg, u8 bitNum)
 {
 	REGs_GPIO[reg] |= 1u<<bitNum;
 }
 
-void gpioClearBit(u16 reg, u8 bitNum)
+void GPIO_clearBit(u16 reg, u8 bitNum)
 {
 	REGs_GPIO[reg] &= ~(1u<<bitNum);
 }
diff --git a/source/arm11/interrupt.c b/source/arm11/interrupt.c
index 667dacf..74e3bb4 100644
--- a/source/arm11/interrupt.c
+++ b/source/arm11/interrupt.c
@@ -106,12 +106,12 @@
 		REG_CPU_II_EOI = tmp; // End of interrupt
 	} while(tmp != 1023);
 
-	__asm__ __volatile__("cpsie i" : :);
+	leaveCriticalSection(); // Enables interrupts
 }
 
 void IRQ_registerHandler(Interrupt id, u8 prio, u8 cpuMask, bool levHighActive, void (*irqHandler)(void))
 {
-	// TODO: Enter critical section
+	enterCriticalSection();
 
 	const u32 cpuId = getCpuId();
 
@@ -137,30 +137,30 @@
 
 	REGs_GID_ENA_SET[id>>5] = 1u<<(id % 32);
 
-	// TODO: Leave critical section
+	leaveCriticalSection();
 }
 
 void IRQ_unregisterHandler(Interrupt id)
 {
-	// TODO: Enter critical section
+	enterCriticalSection();
 
 	REGs_GID_ENA_CLR[id>>5] = 1u<<(id % 32);
 
 	if(id < 16) privIrqHandlerTable[getCpuId()][id] = (void (*)(void))NULL;
 	else irqHandlerTable[id - 16] = (void (*)(void))NULL;
 
-	// TODO: Leave critical section
+	leaveCriticalSection();
 }
 
 void IRQ_setPriority(Interrupt id, u8 prio)
 {
-	// TODO: Enter critical section
+	enterCriticalSection();
 
 	u32 shift = (id % 4 * 8) + 4;
 	u32 tmp = REGs_GID_IPRIO[id>>2] & ~(0xFu<<shift);
 	REGs_GID_IPRIO[id>>2] = tmp | (u32)prio<<shift;
 
-	// TODO: Leave critical section
+	leaveCriticalSection();
 }
 
 void softwareInterrupt(Interrupt id, u8 cpuMask)
diff --git a/source/arm11/main.c b/source/arm11/main.c
index 731c8a7..f16c184 100644
--- a/source/arm11/main.c
+++ b/source/arm11/main.c
@@ -5,6 +5,7 @@
 #include "gfx.h"
 #include "pxi.h"
 #include "arm11/interrupt.h"
+#include "arm11/gpio.h"
 #include "arm11/firm.h"
 
 extern bool battery_ok(void);
@@ -17,8 +18,14 @@
 
 	hardwareInit();
 
+	IRQ_registerHandler(IRQ_PXI_SYNC, 14, 0, true, NULL);
+	IRQ_registerHandler(IRQ_MCU_HID, 14, 0, true, NULL);
+	GPIO_setBit(19, 9); // This enables the MCU HID IRQ
+
 	for(;;)
 	{
+		waitForInterrupt();
+
 		bool successFlag;
 		u32 cmdCode = PXI_tryRecvWord(&successFlag);
 
@@ -79,15 +86,12 @@
 		
 		if(!(hidstate & MCU_HID_HOME_BUTTON_NOT_HELD))
 			PXI_trySendWord(PXI_RPL_HOME_HELD);
-
-		// wait a bit, don't spam the i2c bus
-		wait(0x8000);
 	}
 
 start_firmlaunch:
 	gfx_deinit(); // TODO: Let ARM9 decide when to deinit gfx
 
-	IRQ_setPriority(IRQ_MPCORE_SW1, 0xE); // Needed by NATIVE_FIRM
+	IRQ_setPriority(IRQ_MPCORE_SW1, 14); // Needed by NATIVE_FIRM
 
 	firm_launch();