diff --git a/BizHawk.Emulation.Cores/Consoles/Sega/gpgx/GPGX.ISettable.cs b/BizHawk.Emulation.Cores/Consoles/Sega/gpgx/GPGX.ISettable.cs
index 9269b0d566e..e5ce32ed4c6 100644
--- a/BizHawk.Emulation.Cores/Consoles/Sega/gpgx/GPGX.ISettable.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Sega/gpgx/GPGX.ISettable.cs
@@ -118,6 +118,20 @@ public class GPGXSettings
 			[DefaultValue((short)1)]
 			public short HighGain { get; set; }
 
+			[DeepEqualsIgnore]
+			[JsonIgnore]
+			private bool _Backdrop;
+
+			[DisplayName("Use custom backdrop color")]
+			[Description("Filler when layers are off")]
+			[DefaultValue((bool)false)]
+			public bool Backdrop { get { return _Backdrop; } set { _Backdrop = value; } }
+
+			[DisplayName("Custom backdrop color")]
+			[Description("Magic pink (0xffff00ff) by default")]
+			[DefaultValue((uint)0xffff00ff)]
+			public uint BackdropColor { get; set; }
+
 			public GPGXSettings()
 			{
 				SettingsUtil.SetDefaultValues(this);
@@ -135,6 +149,7 @@ public LibGPGX.DrawMask GetDrawMask()
 				if (DrawBGB) ret |= LibGPGX.DrawMask.BGB;
 				if (DrawBGW) ret |= LibGPGX.DrawMask.BGW;
 				if (DrawObj) ret |= LibGPGX.DrawMask.Obj;
+				if (Backdrop) ret |= LibGPGX.DrawMask.Backdrop;
 				return ret;
 			}
 
@@ -153,7 +168,8 @@ public LibGPGX.InitSettings GetNativeSettings()
 					HighFreq = HighFreq,
 					LowGain = LowGain,
 					MidGain = MidGain,
-					HighGain = HighGain
+					HighGain = HighGain,
+					BackdropColor = BackdropColor
 				};
 			}
 		}
diff --git a/BizHawk.Emulation.Cores/Consoles/Sega/gpgx/LibGPGX.cs b/BizHawk.Emulation.Cores/Consoles/Sega/gpgx/LibGPGX.cs
index 10f0a04e119..6605d837223 100644
--- a/BizHawk.Emulation.Cores/Consoles/Sega/gpgx/LibGPGX.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Sega/gpgx/LibGPGX.cs
@@ -45,6 +45,7 @@ public enum FilterType : byte
 			public short LowGain;
 			public short MidGain;
 			public short HighGain;
+			public uint BackdropColor;
 		}
 
 		[DllImport("libgenplusgx.dll", CallingConvention = CallingConvention.Cdecl)]
@@ -334,7 +335,8 @@ public enum DrawMask : int
 			BGA = 1,
 			BGB = 2,
 			BGW = 4,
-			Obj = 8
+			Obj = 8,
+			Backdrop = 16
 		}
 
 		[DllImport("libgenplusgx.dll", CallingConvention = CallingConvention.Cdecl)]
diff --git a/genplus-gx/cinterface/cinterface.c b/genplus-gx/cinterface/cinterface.c
index 4995ad85982..9bbdb0f87f4 100644
--- a/genplus-gx/cinterface/cinterface.c
+++ b/genplus-gx/cinterface/cinterface.c
@@ -37,7 +37,10 @@ static int nsamples;
 int cinterface_render_bga = 1;
 int cinterface_render_bgb = 1;
 int cinterface_render_bgw = 1;
-int cinterface_render_obj = 0;
+int cinterface_render_obj = 1;
+uint8 cinterface_custom_backdrop = 0;
+uint32 cinterface_custom_backdrop_color = 0xffff00ff; // pink
+extern uint8 border;
 
 #define GPGX_EX __declspec(dllexport)
 
@@ -493,6 +496,7 @@ struct InitSettings
 	int16_t LowGain;
 	int16_t MidGain;
 	int16_t HighGain;
+	uint32_t BackdropColor;
 };
 
 GPGX_EX int gpgx_init(const char *feromextension, int (*feload_archive_cb)(const char *filename, unsigned char *buffer, int maxsize), int sixbutton, char system_a, char system_b, int region, struct InitSettings *settings)
@@ -553,6 +557,8 @@ GPGX_EX int gpgx_init(const char *feromextension, int (*feload_archive_cb)(const
 	input.system[0] = system_a;
 	input.system[1] = system_b;
 
+	cinterface_custom_backdrop_color = settings->BackdropColor;
+
 	// apparently, the only part of config.input used is the padtype identifier,
 	// and that's used only for choosing pad type when system_md
 	{
@@ -600,6 +606,11 @@ GPGX_EX void gpgx_set_draw_mask(int mask)
 	cinterface_render_bgb = !!(mask & 2);
 	cinterface_render_bgw = !!(mask & 4);
 	cinterface_render_obj = !!(mask & 8);
+	cinterface_custom_backdrop = !!(mask & 16);
+	if (cinterface_custom_backdrop)
+		color_update_m5(0, 0);
+	else
+		color_update_m5(0x00, *(uint16 *)&cram[border << 1]);
 }
 
 typedef struct
diff --git a/genplus-gx/core/vdp_ctrl.c b/genplus-gx/core/vdp_ctrl.c
index 5d1943bbb4c..fab96d1b1e2 100644
--- a/genplus-gx/core/vdp_ctrl.c
+++ b/genplus-gx/core/vdp_ctrl.c
@@ -125,7 +125,7 @@ static const uint8 shift_table[]        = { 6, 7, 0, 8 };
 static const uint8 col_mask_table[]     = { 0x0F, 0x1F, 0x0F, 0x3F };
 static const uint16 row_mask_table[]    = { 0x0FF, 0x1FF, 0x2FF, 0x3FF };
 
-static uint8 border;          /* Border color index */
+uint8 border;          /* Border color index */
 static uint8 pending;         /* Pending write flag */
 static uint8 code;            /* Code register */
 static uint8 dma_type;        /* DMA mode */
diff --git a/genplus-gx/core/vdp_render.c b/genplus-gx/core/vdp_render.c
index 2e0cf7a54cd..6d955be73e4 100644
--- a/genplus-gx/core/vdp_render.c
+++ b/genplus-gx/core/vdp_render.c
@@ -48,6 +48,8 @@ extern int cinterface_render_bga;
 extern int cinterface_render_bgb;
 extern int cinterface_render_bgw;
 extern int cinterface_render_obj;
+extern uint8 cinterface_custom_backdrop;
+extern uint32 cinterface_custom_backdrop_color;
 
 /*** NTSC Filters ***/
 extern md_ntsc_t *md_ntsc;
@@ -1123,22 +1125,29 @@ void color_update_m5(int index, unsigned int data)
     data &= 0x49;
   }
 
-  if(reg[12] & 0x08)
+  if (index == 0 && cinterface_custom_backdrop)
   {
-    /* Mode 5 (Shadow/Normal/Highlight) */
-    pixel[0x00 | index] = pixel_lut[0][data];
-    pixel[0x40 | index] = pixel_lut[1][data];
-    pixel[0x80 | index] = pixel_lut[2][data];
+    pixel[0x00] = pixel[0x40] = pixel[0x80] = cinterface_custom_backdrop_color;
   }
   else
   {
-    /* Mode 5 (Normal) */
-    data = pixel_lut[1][data];
-
-    /* Input pixel: xxiiiiii */
-    pixel[0x00 | index] = data;
-    pixel[0x40 | index] = data;
-    pixel[0x80 | index] = data;
+    if(reg[12] & 0x08)
+    {
+      /* Mode 5 (Shadow/Normal/Highlight) */
+      pixel[0x00 | index] = pixel_lut[0][data];
+      pixel[0x40 | index] = pixel_lut[1][data];
+      pixel[0x80 | index] = pixel_lut[2][data];
+    }
+    else
+    {
+      /* Mode 5 (Normal) */
+      data = pixel_lut[1][data];
+    
+      /* Input pixel: xxiiiiii */
+      pixel[0x00 | index] = data;
+      pixel[0x40 | index] = data;
+      pixel[0x80 | index] = data;
+    }
   }
 }
 
@@ -1707,47 +1716,47 @@ void render_bg_m5_vs(int line)
 
   if (cinterface_render_bgb)
   {
-  if(shift)
-  {
-    /* Plane B vertical scroll */
-    v_line = (line + yscroll) & pf_row_mask;
-
-    /* Plane B name table */
-    nt = (uint32 *)&vram[ntbb + (((v_line >> 3) << pf_shift) & 0x1FC0)];
-
-    /* Pattern row index */
-    v_line = (v_line & 7) << 3;
-
-    /* Plane B line buffer */
-    dst = (uint32 *)&linebuf[0][0x10 + shift];
-
-    atbuf = nt[(index - 1) & pf_col_mask];
-    DRAW_COLUMN(atbuf, v_line)
-  }
-  else
-  {
-    /* Plane B line buffer */
-    dst = (uint32 *)&linebuf[0][0x20];
-  }
+    if(shift)
+    {
+      /* Plane B vertical scroll */
+      v_line = (line + yscroll) & pf_row_mask;
+    
+      /* Plane B name table */
+      nt = (uint32 *)&vram[ntbb + (((v_line >> 3) << pf_shift) & 0x1FC0)];
+    
+      /* Pattern row index */
+      v_line = (v_line & 7) << 3;
+    
+      /* Plane B line buffer */
+      dst = (uint32 *)&linebuf[0][0x10 + shift];
+    
+      atbuf = nt[(index - 1) & pf_col_mask];
+      DRAW_COLUMN(atbuf, v_line)
+    }
+    else
+    {
+      /* Plane B line buffer */
+      dst = (uint32 *)&linebuf[0][0x20];
+    }
 
-  for(column = 0; column < end; column++, index++)
-  {
-    /* Plane B vertical scroll */
+    for(column = 0; column < end; column++, index++)
+    {
+      /* Plane B vertical scroll */
 #ifdef LSB_FIRST
-    v_line = (line + (vs[column] >> 16)) & pf_row_mask;
+      v_line = (line + (vs[column] >> 16)) & pf_row_mask;
 #else
-    v_line = (line + vs[column]) & pf_row_mask;
+      v_line = (line + vs[column]) & pf_row_mask;
 #endif
-
-    /* Plane B name table */
-    nt = (uint32 *)&vram[ntbb + (((v_line >> 3) << pf_shift) & 0x1FC0)];
-
-    /* Pattern row index */
-    v_line = (v_line & 7) << 3;
-
-    atbuf = nt[index & pf_col_mask];
-    DRAW_COLUMN(atbuf, v_line)
-  }
+    
+      /* Plane B name table */
+      nt = (uint32 *)&vram[ntbb + (((v_line >> 3) << pf_shift) & 0x1FC0)];
+    
+      /* Pattern row index */
+      v_line = (v_line & 7) << 3;
+    
+      atbuf = nt[index & pf_col_mask];
+      DRAW_COLUMN(atbuf, v_line)
+    }
   }
   else
   {
@@ -1902,30 +1911,30 @@ void render_bg_m5_im2(int line)
   uint32 *nt;
   if (cinterface_render_bgb)
   {
-  nt = (uint32 *)&vram[ntbb + (((v_line >> 3) << pf_shift) & 0x1FC0)];
-
-  /* Pattern row index */
-  v_line = (((v_line & 7) << 1) | odd) << 3;
-
-  if(shift)
-  {
-    /* Plane B line buffer */
-    dst = (uint32 *)&linebuf[0][0x10 + shift];
-
-    atbuf = nt[(index - 1) & pf_col_mask];
-    DRAW_COLUMN_IM2(atbuf, v_line)
-  }
-  else
-  {
-    /* Plane B line buffer */
-    dst = (uint32 *)&linebuf[0][0x20];
-  }
-
-  for(column = 0; column < end; column++, index++)
-  {
-    atbuf = nt[index & pf_col_mask];
-    DRAW_COLUMN_IM2(atbuf, v_line)
-  }
+    nt = (uint32 *)&vram[ntbb + (((v_line >> 3) << pf_shift) & 0x1FC0)];
+    
+    /* Pattern row index */
+    v_line = (((v_line & 7) << 1) | odd) << 3;
+    
+    if(shift)
+    {
+      /* Plane B line buffer */
+      dst = (uint32 *)&linebuf[0][0x10 + shift];
+    
+      atbuf = nt[(index - 1) & pf_col_mask];
+      DRAW_COLUMN_IM2(atbuf, v_line)
+    }
+    else
+    {
+      /* Plane B line buffer */
+      dst = (uint32 *)&linebuf[0][0x20];
+    }
+    
+    for(column = 0; column < end; column++, index++)
+    {
+      atbuf = nt[index & pf_col_mask];
+      DRAW_COLUMN_IM2(atbuf, v_line)
+    }
   }
   else
   {
@@ -2073,47 +2082,47 @@ void render_bg_m5_im2_vs(int line)
 
   if (cinterface_render_bgb)
   {
-  if(shift)
-  {
-    /* Plane B vertical scroll */
-    v_line = (line + yscroll) & pf_row_mask;
-
-    /* Plane B name table */
-    nt = (uint32 *)&vram[ntbb + (((v_line >> 3) << pf_shift) & 0x1FC0)];
-
-    /* Pattern row index */
-    v_line = (((v_line & 7) << 1) | odd) << 3;
-
-    /* Plane B line buffer */
-    dst = (uint32 *)&linebuf[0][0x10 + shift];
-
-    atbuf = nt[(index - 1) & pf_col_mask];
-    DRAW_COLUMN_IM2(atbuf, v_line)
-  }
-  else
-  {
-    /* Plane B line buffer */
-    dst = (uint32 *)&linebuf[0][0x20];
-  }
-
-  for(column = 0; column < end; column++, index++)
-  {
-    /* Plane B vertical scroll */
+    if(shift)
+    {
+      /* Plane B vertical scroll */
+      v_line = (line + yscroll) & pf_row_mask;
+    
+      /* Plane B name table */
+      nt = (uint32 *)&vram[ntbb + (((v_line >> 3) << pf_shift) & 0x1FC0)];
+    
+      /* Pattern row index */
+      v_line = (((v_line & 7) << 1) | odd) << 3;
+    
+      /* Plane B line buffer */
+      dst = (uint32 *)&linebuf[0][0x10 + shift];
+    
+      atbuf = nt[(index - 1) & pf_col_mask];
+      DRAW_COLUMN_IM2(atbuf, v_line)
+    }
+    else
+    {
+      /* Plane B line buffer */
+      dst = (uint32 *)&linebuf[0][0x20];
+    }
+    
+    for(column = 0; column < end; column++, index++)
+    {
+      /* Plane B vertical scroll */
 #ifdef LSB_FIRST
-    v_line = (line + (vs[column] >> 17)) & pf_row_mask;
+      v_line = (line + (vs[column] >> 17)) & pf_row_mask;
 #else
-    v_line = (line + (vs[column] >> 1)) & pf_row_mask;
+      v_line = (line + (vs[column] >> 1)) & pf_row_mask;
 #endif
-
-    /* Plane B name table */
-    nt = (uint32 *)&vram[ntbb + (((v_line >> 3) << pf_shift) & 0x1FC0)];
-
-    /* Pattern row index */
-    v_line = (((v_line & 7) << 1) | odd) << 3;
-
-    atbuf = nt[index & pf_col_mask];
-    DRAW_COLUMN_IM2(atbuf, v_line)
-  }
+    
+      /* Plane B name table */
+      nt = (uint32 *)&vram[ntbb + (((v_line >> 3) << pf_shift) & 0x1FC0)];
+    
+      /* Pattern row index */
+      v_line = (((v_line & 7) << 1) | odd) << 3;
+    
+      atbuf = nt[index & pf_col_mask];
+      DRAW_COLUMN_IM2(atbuf, v_line)
+    }
   }
   else
   {
diff --git a/output/dll/libgenplusgx.dll b/output/dll/libgenplusgx.dll
index 12c1847eae2..1dcce9a51ba 100644
Binary files a/output/dll/libgenplusgx.dll and b/output/dll/libgenplusgx.dll differ