diff --git a/Makefile b/Makefile
index 3369996..e77cdbc 100644
--- a/Makefile
+++ b/Makefile
@@ -23,7 +23,7 @@ endif
 BUILD		:=	build
 SOURCES		:=	source source/common source/filesys source/crypto source/fatfs source/nand source/virtual source/game source/gamecart source/quicklz
 DATA		:=	data
-INCLUDES	:=	source source/common source/font source/filesys source/crypto source/fatfs source/nand source/virtual source/game source/gamecart source/quicklz
+INCLUDES	:=	common source source/common source/font source/filesys source/crypto source/fatfs source/nand source/virtual source/game source/gamecart source/quicklz
 
 #---------------------------------------------------------------------------------
 # options for code generation
diff --git a/common/cpu.h b/common/cpu.h
new file mode 100644
index 0000000..4661c1e
--- /dev/null
+++ b/common/cpu.h
@@ -0,0 +1,68 @@
+/*
+ Written by Wolfvak, specially sublicensed under the GPLv2
+ Read LICENSE for more details
+*/
+
+#pragma once
+#include <types.h>
+
+#define asm __asm volatile
+
+static inline u32 CPU_ReadCPSR(void)
+{
+    u32 cpsr;
+    asm("mrs %0, cpsr\n\t":"=r"(cpsr));
+    return cpsr;
+}
+
+static inline void CPU_WriteCPSR_c(u32 cpsr)
+{
+    asm("msr cpsr_c, %0\n\t"::"r"(cpsr));
+    return;
+}
+
+static inline u32 CPU_ReadCR(void)
+{
+    u32 cr;
+    asm("mrc p15, 0, %0, c1, c0, 0\n\t":"=r"(cr));
+    return cr;
+}
+
+static inline void CPU_WriteCR(u32 cr)
+{
+    asm("mcr p15, 0, %0, c1, c0, 0\n\t"::"r"(cr));
+    return;
+}
+
+static inline void CPU_DisableIRQ(void)
+{
+    #ifdef ARM9
+    CPU_WriteCPSR_c(CPU_ReadCPSR() | (0xC0));
+    #else
+    asm("cpsid if\n\t");
+    #endif
+    return;
+}
+
+static inline void CPU_EnableIRQ(void)
+{
+    #ifdef ARM9
+    CPU_WriteCPSR_c(CPU_ReadCPSR() & ~(0xC0));
+    #else
+    asm("cpsie if\n\t");
+    #endif
+    return;
+}
+
+static inline void CPU_EnterCritical(u32 *ss)
+{
+    *ss = CPU_ReadCPSR();
+    CPU_DisableIRQ();
+    return;
+}
+
+static inline void CPU_LeaveCritical(u32 *ss)
+{
+    CPU_WriteCPSR_c(*ss);
+    return;
+}
diff --git a/common/pxi.h b/common/pxi.h
new file mode 100644
index 0000000..63b4fa3
--- /dev/null
+++ b/common/pxi.h
@@ -0,0 +1,101 @@
+/*
+ Written by Wolfvak, specially sublicensed under the GPLv2
+ Read LICENSE for more details
+*/
+
+#pragma once
+#include <types.h>
+
+#ifdef ARM9
+#define PXI_BASE (0x10008000)
+#define IRQ_PXI_SYNC (12)
+#else
+#define PXI_BASE (0x10163000)
+#define IRQ_PXI_SYNC (80)
+#endif
+
+enum {
+    PXI_NOCMD = 0,
+    PXI_SETBRIGHTNESS = 1
+};
+
+#define PXI_SYNC_RECV ((volatile uint8_t*)(PXI_BASE + 0x00))
+#define PXI_SYNC_SEND ((volatile uint8_t*)(PXI_BASE + 0x01))
+#define PXI_SYNC_IRQ  ((volatile uint8_t*)(PXI_BASE + 0x03))
+#define PXI_CNT       ((volatile uint16_t*)(PXI_BASE + 0x04))
+#define PXI_SEND      ((volatile uint32_t*)(PXI_BASE + 0x08))
+#define PXI_RECV      ((volatile uint32_t*)(PXI_BASE + 0x0C))
+
+#define PXI_CNT_SEND_FIFO_EMPTY       (1<<0)
+#define PXI_CNT_SEND_FIFO_FULL        (1<<1)
+#define PXI_CNT_SEND_FIFO_EMPTY_IRQ   (1<<2)
+#define PXI_CNT_SEND_FIFO_FLUSH       (1<<3)
+#define PXI_CNT_RECV_FIFO_EMPTY       (1<<8)
+#define PXI_CNT_RECV_FIFO_FULL        (1<<9)
+#define PXI_CNT_RECV_FIFO_NEMPTY_IRQ  (1<<10)
+#define PXI_CNT_ERROR_ACK             (1<<14)
+#define PXI_CNT_ENABLE_FIFO           (1<<15)
+
+#define PXI_SYNC_TRIGGER_MPCORE (1<<5)
+#define PXI_SYNC_TRIGGER_OLDARM (1<<6)
+#define PXI_SYNC_ENABLE_IRQ     (1<<7)
+
+static inline void PXI_SetRemote(u8 msg)
+{
+    *PXI_SYNC_SEND = msg;
+}
+
+static inline u8 PXI_GetRemote(void)
+{
+    return *PXI_SYNC_RECV;
+}
+
+static inline void PXI_EnableIRQ(void)
+{
+    *PXI_SYNC_IRQ = PXI_SYNC_ENABLE_IRQ;
+}
+
+static inline void PXI_DisableIRQ(void)
+{
+    *PXI_SYNC_IRQ = 0;
+}
+
+static inline void PXI_Wait(void)
+{
+    while(PXI_GetRemote() != PXI_NOCMD);
+}
+
+static inline void PXI_Sync(void)
+{
+    #ifdef ARM9
+    *PXI_SYNC_IRQ |= PXI_SYNC_TRIGGER_MPCORE;
+    #else
+    *PXI_SYNC_IRQ |= PXI_SYNC_TRIGGER_OLDARM;
+    #endif
+}
+
+static inline void PXI_Reset(void)
+{
+    *PXI_SYNC_SEND = 0;
+    *PXI_SYNC_IRQ = 0;
+    *PXI_CNT = PXI_CNT_SEND_FIFO_FLUSH | PXI_CNT_ENABLE_FIFO;
+}
+
+static inline void PXI_Send(u32 w)
+{
+    while(*PXI_CNT & PXI_CNT_SEND_FIFO_FULL);
+    do {
+        *PXI_SEND = w;
+    } while(*PXI_CNT & PXI_CNT_ERROR_ACK);
+    return;
+}
+
+static inline u32 PXI_Recv(void)
+{
+    u32 ret;
+    while(*PXI_CNT & PXI_CNT_RECV_FIFO_EMPTY);
+    do {
+        ret = *PXI_RECV;
+    } while(*PXI_CNT & PXI_CNT_ERROR_ACK);
+    return ret;
+}
diff --git a/common/types.h b/common/types.h
new file mode 100644
index 0000000..2d52816
--- /dev/null
+++ b/common/types.h
@@ -0,0 +1,31 @@
+#pragma once
+
+#ifndef ARM9
+#ifndef ARM11
+#error "Unknown processor"
+#endif
+#endif
+
+#include <stdint.h>
+
+#define BIT(x) (1<<(x))
+
+typedef uint8_t  u8;
+typedef uint16_t u16;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef int64_t s8;
+typedef int64_t s16;
+typedef int64_t s32;
+typedef int64_t s64;
+
+typedef volatile u8 vu8;
+typedef volatile u16 vu16;
+typedef volatile u32 vu32;
+typedef volatile u64 vu64;
+
+typedef volatile s8  vs8;
+typedef volatile s16 vs16;
+typedef volatile s32 vs32;
+typedef volatile s64 vs64;
diff --git a/screeninit/Makefile b/screeninit/Makefile
index 8f563e6..ca57208 100644
--- a/screeninit/Makefile
+++ b/screeninit/Makefile
@@ -12,9 +12,11 @@ dir_source := source
 dir_build := build
 dir_out := ../$(dir_build)
 
-ASFLAGS := -mcpu=mpcore -mfloat-abi=hard
-CFLAGS  := -Wall -Wextra -MMD -MP -mthumb -mthumb-interwork $(ASFLAGS) -fno-builtin -std=c11 -Wno-main -O2 -flto -ffast-math
-LDFLAGS := -nostdlib
+ASFLAGS := -mcpu=mpcore -mfloat-abi=soft
+CFLAGS  := -DARM11 -Wall -Wextra -MMD -MP -marm -mno-thumb-interwork \
+           $(ASFLAGS) -fno-builtin -std=c11 -Wno-main -O2 -flto -ffast-math \
+           -I$(dir_source) -I../common
+LDFLAGS := -nostdlib -nostartfiles
 
 objects = $(patsubst $(dir_source)/%.s, $(dir_build)/%.o, \
           $(patsubst $(dir_source)/%.c, $(dir_build)/%.o, \
diff --git a/screeninit/linker.ld b/screeninit/linker.ld
index fc311e9..c2855bb 100644
--- a/screeninit/linker.ld
+++ b/screeninit/linker.ld
@@ -9,8 +9,10 @@ SECTIONS
     .text   : ALIGN(4) { *(.text.start) *(.text*); . = ALIGN(4); }
     .rodata : ALIGN(4) { *(.rodata*); . = ALIGN(4); }
     .data   : ALIGN(4) { *(.data*); . = ALIGN(8); *(.bss* COMMON); . = ALIGN(8); }
+    .bss    : ALIGN(4) { __bss_start = .; *(.bss*); __bss_end = .; }
 
     . = ALIGN(4);
-    
-    __stack_top = 0x1FFFF800;
+
+    __irq_stack = 0x1FFFF800;
+    __prg_stack = 0x1FFFF400;
 }
diff --git a/screeninit/source/boot.s b/screeninit/source/boot.s
index 711c766..da173fd 100644
--- a/screeninit/source/boot.s
+++ b/screeninit/source/boot.s
@@ -5,8 +5,8 @@
 
 .global __boot
 __boot:
-    @ Disable interrupts and switch to Supervisor
-    cpsid aif, #0x13
+    @ Disable interrupts and switch to IRQ
+    cpsid aif, #0x12
 
     @ Writeback and invalidate caches
     mov r0, #0
@@ -14,7 +14,11 @@ __boot:
     mcr p15, 0, r0, c7, c14, 0
     mcr p15, 0, r0, c7, c10, 4
 
-    ldr sp, =__stack_top
+    ldr sp, =__irq_stack
+
+    @ Switch to SVC
+    cpsid aif, #0x13
+    ldr sp, =__prg_stack
 
     @ Reset values
     ldr r0, =0x00054078
@@ -26,6 +30,14 @@ __boot:
     mcr p15, 0, r1, c1, c0, 1
     mcr p15, 0, r2, c1, c0, 2
 
+    ldr r0, =__bss_start
+    ldr r1, =__bss_end
+    mov r2, #0
+    .Lclearbss:
+        str r2, [r0], #4
+        cmp r0, r1
+        blt .Lclearbss
+
     bl main
 
     b __boot
diff --git a/screeninit/source/gic.c b/screeninit/source/gic.c
new file mode 100644
index 0000000..2236cd1
--- /dev/null
+++ b/screeninit/source/gic.c
@@ -0,0 +1,57 @@
+/*
+ Written by Wolfvak, specially sublicensed under the GPLv2
+ Read LICENSE for more details
+*/
+
+#include <types.h>
+#include <cpu.h>
+#include <gic.h>
+
+#define IRQ_BASE ((vu32*)0x1FFFFFA0)
+
+irq_handler handler_table[MAX_IRQ];
+
+void __attribute__((interrupt("IRQ"))) gic_irq_handler(void)
+{
+    u32 xrq, ss;
+    CPU_EnterCritical(&ss);
+    xrq = *GIC_IRQACK;
+    if (xrq < MAX_IRQ && handler_table[xrq]) {
+        (handler_table[xrq])(xrq);
+    }
+    *GIC_IRQEND = xrq;
+    CPU_LeaveCritical(&ss);
+    return;
+}
+
+void GIC_Configure(u32 irq_id, irq_handler hndl)
+{
+    handler_table[irq_id] = hndl;
+    DIC_CLRENABLE[irq_id/32] |= BIT(irq_id & 0x1F);
+    DIC_SETENABLE[irq_id/32] |= BIT(irq_id & 0x1F);
+    DIC_PROCTGT[irq_id] = 1;
+    return;
+}
+
+void GIC_Reset(void)
+{
+    *GIC_CONTROL = 0;
+    *GIC_PRIOMASK = ~0;
+
+    for (int i = 0; i < (BIT(9)-1); i++) {
+        *GIC_IRQEND |= i;
+    }
+
+    *DIC_CONTROL = 0;
+    for (int i = 0; i < (0x20/4); i++) {
+        DIC_CLRENABLE[i] = ~0;
+        DIC_PRIORITY[i] = 0;
+    }
+
+    *DIC_CONTROL = 1;
+    *GIC_CONTROL = 1;
+
+    IRQ_BASE[1] = (u32)gic_irq_handler;
+    IRQ_BASE[0] = 0xE51FF004;
+    return;
+}
diff --git a/screeninit/source/gic.h b/screeninit/source/gic.h
new file mode 100644
index 0000000..82ae829
--- /dev/null
+++ b/screeninit/source/gic.h
@@ -0,0 +1,56 @@
+/*
+ Written by Wolfvak, specially sublicensed under the GPLv2
+ Read LICENSE for more details
+*/
+
+#pragma once
+#include <types.h>
+
+typedef void (*irq_handler)(u32);
+
+#define MAX_IRQ  (0x80)
+
+#define GIC_BASE (0x17E00100)
+#define DIC_BASE (0x17E01000)
+
+/* Setting bit 0 enables the GIC */
+#define GIC_CONTROL   ((vu32*)(GIC_BASE + 0x00))
+/* Bits [7:0] control the min priority accepted */
+#define GIC_PRIOMASK  ((vu32*)(GIC_BASE + 0x04))
+/* When an IRQ occurrs, this register holds the IRQ ID */
+#define GIC_IRQACK    ((vu32*)(GIC_BASE + 0x0C))
+/* Write the IRQ ID here to acknowledge it */
+#define GIC_IRQEND    ((vu32*)(GIC_BASE + 0x10))
+
+
+/* Setting bit 0 enables the DIC */
+#define DIC_CONTROL   ((vu32*)(DIC_BASE + 0x000))
+/*
+ Write here to enable an IRQ ID
+ The register address is DIC_SETENABLE + (N/32)*4 and its
+ corresponding bit index is (N%32)
+*/
+#define DIC_SETENABLE ((vu32*)(DIC_BASE + 0x100))
+
+/* same as above but disables the IRQ */
+#define DIC_CLRENABLE ((vu32*)(DIC_BASE + 0x180))
+
+/* sets the IRQ priority */
+#define DIC_PRIORITY  ((vu32*)(DIC_BASE + 0x400))
+
+/* specifies which CPUs are allowed to be forwarded the IRQ */
+#define DIC_PROCTGT   ((vu8*)(DIC_BASE + 0x800))
+
+/*
+ each irq has 2 bits assigned
+ bit 0 = 0: uses 1-N model
+         1: uses N-N model
+
+ bit 1 = 0: level high active
+         1: rising edge sensitive
+ */
+#define DIC_CFGREG    ((vu32*)(DIC_BASE + 0xC00))
+
+void gic_irq_handler(void);
+void GIC_Configure(u32 irq_id, irq_handler hndl);
+void GIC_Reset(void);
diff --git a/screeninit/source/main.c b/screeninit/source/main.c
index 9c11c14..a75e98b 100644
--- a/screeninit/source/main.c
+++ b/screeninit/source/main.c
@@ -1,26 +1,33 @@
 // screeninit source taken over from https://github.com/AuroraWright/arm9loaderhax/tree/master/payload_stage2/arm11
 // check there for license info
 // thanks go to AuroraWright
-#include "types.h"
+#include <types.h>
+#include <cpu.h>
+#include <gic.h>
+#include <pxi.h>
 
 // see: https://github.com/AuroraWright/Luma3DS/blob/53209b9be0c264af00fb81b32146d27f0d9498ac/source/screen.h#L32-L34
 #define PDN_GPU_CNT (*(vu8  *)0x10141200)
 #define ARESCREENSINITIALIZED (PDN_GPU_CNT != 1)
 
-#define BRIGHTNESS (0xBF)
+#define BASE_BRIGHTNESS (0x1F)
 
-void main(void)
+static volatile struct fb {
+     u8 *top_left;
+     u8 *top_right;
+     u8 *bottom;
+} *const fb = (volatile struct fb *)0x23FFFE00;
+
+void screen_init(void)
 {
     char do_disco = !ARESCREENSINITIALIZED;
-    vu32 *arm11Entry = (vu32 *)0x1FFFFFFC;
-    u32 entry;
 
     *(vu32 *)0x10141200 = 0x1007F;
     *(vu32 *)0x10202014 = 0x00000001;
     *(vu32 *)0x1020200C &= 0xFFFEFFFE;
 
-    *(vu32 *)0x10202240 = BRIGHTNESS;
-    *(vu32 *)0x10202A40 = BRIGHTNESS;
+    *(vu32 *)0x10202240 = BASE_BRIGHTNESS;
+    *(vu32 *)0x10202A40 = BASE_BRIGHTNESS;
     *(vu32 *)0x10202244 = 0x1023E;
     *(vu32 *)0x10202A44 = 0x1023E;
 
@@ -107,21 +114,59 @@ void main(void)
          *REGs_PSC1 = (vu32 *)0x10400020;
 
     REGs_PSC0[0] = (u32)fb->top_left >> 3; //Start address
-    REGs_PSC0[1] = (u32)(fb->top_left + SCREEN_TOP_FBSIZE) >> 3; //End address
+    REGs_PSC0[1] = (u32)(fb->top_left + 0x46500) >> 3; //End address
     REGs_PSC0[2] = 0; //Fill value
     REGs_PSC0[3] = (2 << 8) | 1; //32-bit pattern; start
 
     REGs_PSC1[0] = (u32)fb->bottom >> 3; //Start address
-    REGs_PSC1[1] = (u32)(fb->bottom + SCREEN_BOTTOM_FBSIZE) >> 3; //End address
+    REGs_PSC1[1] = (u32)(fb->bottom + 0x38400) >> 3; //End address
     REGs_PSC1[2] = 0; //Fill value
     REGs_PSC1[3] = (2 << 8) | 1; //32-bit pattern; start
 
     while(!((REGs_PSC0[3] & 2) && (REGs_PSC1[3] & 2)));
+    return;
+}
+
+void set_brightness(u8 brightness)
+{
+    *(vu32 *)0x10202240 = brightness;
+    *(vu32 *)0x10202A40 = brightness;
+}
+
+void pxi_interrupt_handler(__attribute__((unused)) u32 xrq_n)
+{
+    u8 msg = PXI_GetRemote();
+    switch(msg) {
+    case PXI_NOCMD:
+        break;
+    case PXI_SETBRIGHTNESS:
+        set_brightness(PXI_Recv());
+        break;
+    }
+    PXI_SetRemote(PXI_NOCMD);
+    return;
+}
+
+void main(void)
+{
+    vu32 *arm11Entry = (vu32 *)0x1FFFFFFC;
+    u32 entry;
+
+    PXI_Reset();
+    GIC_Reset();
+    screen_init();
 
     // Clear ARM11 entrypoint
     *arm11Entry = 0;
 
+    GIC_Configure(IRQ_PXI_SYNC, pxi_interrupt_handler);
+    PXI_EnableIRQ();
+    CPU_EnableIRQ();
+
     //Wait for the entrypoint to be set, then branch to it
     while((entry=*arm11Entry) == 0);
+
+    CPU_DisableIRQ();
+    PXI_DisableIRQ();
     ((void (*)())(entry))();
 }
diff --git a/screeninit/source/types.h b/screeninit/source/types.h
deleted file mode 100644
index 3f04590..0000000
--- a/screeninit/source/types.h
+++ /dev/null
@@ -1,25 +0,0 @@
-#pragma once
-
-#include <stdint.h>
-
-//Common data types
-typedef uint8_t u8;
-typedef uint16_t u16;
-typedef uint32_t u32;
-typedef uint64_t u64;
-typedef volatile u8 vu8;
-typedef volatile u16 vu16;
-typedef volatile u32 vu32;
-typedef volatile u64 vu64;
-
-#define SCREEN_TOP_WIDTH     400
-#define SCREEN_BOTTOM_WIDTH  320
-#define SCREEN_HEIGHT        240
-#define SCREEN_TOP_FBSIZE    (3 * SCREEN_TOP_WIDTH * SCREEN_HEIGHT)
-#define SCREEN_BOTTOM_FBSIZE (3 * SCREEN_BOTTOM_WIDTH * SCREEN_HEIGHT)
-
-static volatile struct fb {
-     u8 *top_left;
-     u8 *top_right;
-     u8 *bottom;
-} *const fb = (volatile struct fb *)0x23FFFE00;
diff --git a/source/common/common.h b/source/common/common.h
index 813f737..6ae2bce 100644
--- a/source/common/common.h
+++ b/source/common/common.h
@@ -7,16 +7,7 @@
 #include <ctype.h>
 #include <stdlib.h>
 #include <stdio.h>
-
-#define u8 uint8_t
-#define u16 uint16_t
-#define u32 uint32_t
-#define u64 uint64_t
-
-#define vu8 volatile u8
-#define vu16 volatile u16
-#define vu32 volatile u32
-#define vu64 volatile u64
+#include <types.h>
 
 #define max(a,b) \
     (((a) > (b)) ? (a) : (b))
diff --git a/source/common/hid.c b/source/common/hid.c
index f74931e..af67123 100644
--- a/source/common/hid.c
+++ b/source/common/hid.c
@@ -1,6 +1,7 @@
 #include "hid.h"
 #include "i2c.h"
 #include "timer.h"
+#include "power.h"
 
 u32 InputWait(u32 timeout_sec) {
     static u64 delay = 0;
@@ -23,6 +24,7 @@ u32 InputWait(u32 timeout_sec) {
                 return sd_state ? SD_INSERT : SD_EJECT;
             u8 special_key;
             if ((timer_msec(timer_mcu) >= 64) && (I2C_readRegBuf(I2C_DEV_MCU, 0x10, &special_key, 1))) {
+                CheckBrightness();
                 if (special_key == 0x01)
                     return pad_state | BUTTON_POWER;
                 else if (special_key == 0x04)
diff --git a/source/common/power.c b/source/common/power.c
index f8064c6..74b0030 100644
--- a/source/common/power.c
+++ b/source/common/power.c
@@ -2,6 +2,23 @@
 #include "i2c.h"
 #include "cache.h"
 #include "timer.h"
+#include "pxi.h"
+
+static const u8 br_settings[] = {0x1F, 0x3F, 0x7F, 0xBF};
+static int prev_brightness = -1;
+void CheckBrightness() {
+    u8 curSlider;
+    I2C_readRegBuf(I2C_DEV_MCU, 0x09, &curSlider, 1);
+    curSlider >>= 4;
+    if (curSlider != prev_brightness) {
+        PXI_Wait();
+        PXI_Send(br_settings[curSlider]);
+        PXI_SetRemote(PXI_SETBRIGHTNESS);
+        PXI_Sync();
+        prev_brightness = curSlider;
+    }
+    return;
+}
 
 void ScreenOn() {
     wait_msec(3); // wait 3ms (cause profi200 said so)
diff --git a/source/common/power.h b/source/common/power.h
index 6b751b8..42abc1e 100644
--- a/source/common/power.h
+++ b/source/common/power.h
@@ -2,6 +2,7 @@
 
 #include "common.h"
 
+void CheckBrightness();
 void ScreenOn();
 void Reboot();
 void PowerOff();
diff --git a/source/main.c b/source/main.c
index cffe3f0..00335bf 100644
--- a/source/main.c
+++ b/source/main.c
@@ -1,14 +1,15 @@
 #include "godmode.h"
 #include "power.h"
+#include "pxi.h"
 
 void main(int argc, char** argv)
 {
     (void) argc; // unused for now
     (void) argv; // unused for now
-    
+
     // Screen on
     ScreenOn();
-    
+
     // Run the main program
     if (GodMode() == GODMODE_EXIT_REBOOT) Reboot();
     else PowerOff();