diff --git a/Assets/dll/gpgx.wbx.zst b/Assets/dll/gpgx.wbx.zst
index bb61da0e3a..c30aa68375 100644
Binary files a/Assets/dll/gpgx.wbx.zst and b/Assets/dll/gpgx.wbx.zst differ
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/GPGX.IMemoryDomains.cs b/src/BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/GPGX.IMemoryDomains.cs
index 8f70d3691c..49f16344e8 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/GPGX.IMemoryDomains.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/GPGX.IMemoryDomains.cs
@@ -66,23 +66,7 @@ namespace BizHawk.Emulation.Cores.Consoles.Sega.gpgx
 							(addr, val) =>
 							{
 								if (addr is < 0 or > 0x7F) throw new ArgumentOutOfRangeException(paramName: nameof(addr), addr, message: "address out of range");
-								using (_elf.EnterExit())
-								{
-									var c = *(ushort*)&p![addr & ~1];
-									c = (ushort)(((c & 0x1C0) << 3) | ((c & 0x038) << 2) | ((c & 0x007) << 1));
-									if ((addr & 1) != 0)
-									{
-										c &= 0xFF00;
-										c |= val;
-									}
-									else
-									{
-										c &= 0x00FF;
-										c |= (ushort)(val << 8);
-									}
-									c = (ushort)(((c & 0xE00) >> 3) | ((c & 0x0E0) >> 2) | ((c & 0x00E) >> 1)); 
-									*(ushort*)&p![addr & ~1] = c;
-								}
+								Core.gpgx_poke_cram((int)addr, val);
 							},
 							wordSize: 2));
 					}
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/LibGPGX.cs b/src/BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/LibGPGX.cs
index 2e7f64ecf1..d2aeddbc60 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/LibGPGX.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/LibGPGX.cs
@@ -310,6 +310,9 @@ namespace BizHawk.Emulation.Cores.Consoles.Sega.gpgx
 		[BizImport(CallingConvention.Cdecl, Compatibility = true)]
 		public abstract void gpgx_get_vdp_view([Out] VDPView view);
 
+		[BizImport(CallingConvention.Cdecl)]
+		public abstract void gpgx_poke_cram(int addr, byte value);
+
 		[BizImport(CallingConvention.Cdecl)]
 		public abstract void gpgx_poke_vram(int addr, byte value);
 
diff --git a/waterbox/gpgx/cinterface/cinterface.c b/waterbox/gpgx/cinterface/cinterface.c
index 378c4792e8..1fdd924c7a 100644
--- a/waterbox/gpgx/cinterface/cinterface.c
+++ b/waterbox/gpgx/cinterface/cinterface.c
@@ -343,6 +343,11 @@ GPGX_EX int gpgx_put_sram(const uint8 *data, int size)
 	}
 }
 
+GPGX_EX void gpgx_poke_cram(int addr, uint8 val)
+{
+	write_cram_byte(addr, val);
+}
+
 GPGX_EX void gpgx_poke_vram(int addr, uint8 val)
 {
 	write_vram_byte(addr, val);
diff --git a/waterbox/gpgx/core/vdp_ctrl.c b/waterbox/gpgx/core/vdp_ctrl.c
index a5c530f660..c759865d26 100644
--- a/waterbox/gpgx/core/vdp_ctrl.c
+++ b/waterbox/gpgx/core/vdp_ctrl.c
@@ -194,6 +194,45 @@ static void (*const dma_func[16])(unsigned int length) =
   vdp_dma_copy,vdp_dma_copy,vdp_dma_copy,vdp_dma_copy
 };
 
+void write_cram_byte(int addr, uint8 val)
+{
+	uint16 *p;
+	uint16 data;
+	int index;
+
+	p = (uint16 *)&cram[addr & 0x7E];
+	data = *p;
+	data = ((data & 0x1C0) << 3) | ((data & 0x038) << 2) | ((data & 0x007) << 1);
+
+	if (addr & 1)
+	{
+		data &= 0xFF00;
+		data |= val;
+	}
+	else
+	{
+		data &= 0x00FF;
+		data |= val << 8;
+	}
+
+	data = ((data & 0xE00) >> 3) | ((data & 0x0E0) >> 2) | ((data & 0x00E) >> 1);
+
+	if (*p != data)
+	{
+		index = (addr >> 1) & 0x3F;
+		*p = data;
+
+		if (index & 0x0F)
+		{
+			color_update_m5(index, data);
+		}
+
+		if (index == border)
+		{
+			color_update_m5(0x00, data);
+		}
+	}
+}
 
 void write_vram_byte(int addr, uint8 val)
 {
diff --git a/waterbox/gpgx/core/vdp_ctrl.h b/waterbox/gpgx/core/vdp_ctrl.h
index b3d60f8488..8d3036b284 100644
--- a/waterbox/gpgx/core/vdp_ctrl.h
+++ b/waterbox/gpgx/core/vdp_ctrl.h
@@ -100,6 +100,7 @@ extern unsigned int vdp_hvc_r(unsigned int cycles);
 extern void vdp_test_w(unsigned int data);
 extern int vdp_68k_irq_ack(int int_level);
 
+void write_cram_byte(int addr, uint8 val);
 void write_vram_byte(int addr, uint8 val);
 void flush_vram_cache(void);
 void vdp_invalidate_full_cache(void);