diff --git a/GPU2D.cpp b/GPU2D.cpp
index de3636e7..90064d18 100644
--- a/GPU2D.cpp
+++ b/GPU2D.cpp
@@ -83,6 +83,8 @@ void GPU2D::Reset()
     memset(BGRotC, 0, 2*2);
     memset(BGRotD, 0, 2*2);
 
+    MasterBrightness = 0;
+
     BGExtPalStatus[0] = 0;
     BGExtPalStatus[1] = 0;
     BGExtPalStatus[2] = 0;
@@ -170,6 +172,8 @@ void GPU2D::Write16(u32 addr, u16 val)
     case 0x032: BGRotB[1] = val; return;
     case 0x034: BGRotC[1] = val; return;
     case 0x036: BGRotD[1] = val; return;
+
+    case 0x06C: MasterBrightness = val; return;
     }
 
     //printf("unknown GPU write16 %08X %04X\n", addr, val);
@@ -265,6 +269,50 @@ void GPU2D::DrawScanline(u32 line)
         break;
     }
 
+    // master brightness
+    if ((MasterBrightness >> 14) == 1)
+    {
+        // up
+        u32 factor = MasterBrightness & 0x1F;
+        if (factor > 16) factor = 16;
+
+        for (int i = 0; i < 256; i++)
+        {
+            u32 val = dst[i];
+
+            u32 r = val & 0x00003F;
+            u32 g = val & 0x003F00;
+            u32 b = val & 0x3F0000;
+
+            r += (((0x00003F - r) * factor) >> 4);
+            g += ((((0x003F00 - g) * factor) >> 4) & 0x003F00);
+            b += ((((0x3F0000 - b) * factor) >> 4) & 0x3F0000);
+
+            dst[i] = r | g | b;
+        }
+    }
+    else if ((MasterBrightness >> 14) == 2)
+    {
+        // down
+        u32 factor = MasterBrightness & 0x1F;
+        if (factor > 16) factor = 16;
+
+        for (int i = 0; i < 256; i++)
+        {
+            u32 val = dst[i];
+
+            u32 r = val & 0x00003F;
+            u32 g = val & 0x003F00;
+            u32 b = val & 0x3F0000;
+
+            r -= ((r * factor) >> 4);
+            g -= (((g * factor) >> 4) & 0x003F00);
+            b -= (((b * factor) >> 4) & 0x3F0000);
+
+            dst[i] = r | g | b;
+        }
+    }
+
     // convert to 32-bit RGBA
     for (int i = 0; i < 256; i++)
         dst[i] = ((dst[i] & 0x003F3F3F) << 2) |
diff --git a/GPU2D.h b/GPU2D.h
index 0230802d..89694e88 100644
--- a/GPU2D.h
+++ b/GPU2D.h
@@ -64,6 +64,8 @@ private:
 
     u32 BlendFunc;
 
+    u16 MasterBrightness;
+
     u16 BGExtPalCache[4][16*256];
     u16 OBJExtPalCache[16*256];
     u32 BGExtPalStatus[4];
diff --git a/NDS.cpp b/NDS.cpp
index 0bba278a..1bb758c8 100644
--- a/NDS.cpp
+++ b/NDS.cpp
@@ -1624,12 +1624,12 @@ void ARM9IOWrite16(u32 addr, u16 val)
         return;
     }
 
-    if (addr >= 0x04000000 && addr < 0x04000060)
+    if ((addr >= 0x04000000 && addr < 0x04000060) || (addr == 0x0400006C))
     {
         GPU::GPU2D_A->Write16(addr, val);
         return;
     }
-    if (addr >= 0x04001000 && addr < 0x04001060)
+    if ((addr >= 0x04001000 && addr < 0x04001060) || (addr == 0x0400106C))
     {
         GPU::GPU2D_B->Write16(addr, val);
         return;
diff --git a/melonDS.depend b/melonDS.depend
index adc19479..fe0d65e8 100644
--- a/melonDS.depend
+++ b/melonDS.depend
@@ -10,7 +10,7 @@
 
 1481161027 c:\documents\sources\melonds\types.h
 
-1488281931 source:c:\documents\sources\melonds\nds.cpp
+1488393021 source:c:\documents\sources\melonds\nds.cpp
 	<stdio.h>
 	<string.h>
 	"NDS.h"
@@ -87,13 +87,13 @@
 	"NDS.h"
 	"SPI.h"
 
-1488281814 source:c:\documents\sources\melonds\gpu2d.cpp
+1488396037 source:c:\documents\sources\melonds\gpu2d.cpp
 	<stdio.h>
 	<string.h>
 	"NDS.h"
 	"GPU.h"
 
-1488225922 c:\documents\sources\melonds\gpu2d.h
+1488392627 c:\documents\sources\melonds\gpu2d.h
 
 1481040524 c:\documents\sources\melonds\wifi.h
 
@@ -155,7 +155,7 @@
 	"GPU.h"
 	"FIFO.h"
 
-1488244847 source:c:\documents\sources\melonds\gpu3d_soft.cpp
+1488390544 source:c:\documents\sources\melonds\gpu3d_soft.cpp
 	<stdio.h>
 	<string.h>
 	"NDS.h"