diff --git a/desmume/src/MMU.cpp b/desmume/src/MMU.cpp
index b9d281485..3cb04fb98 100644
--- a/desmume/src/MMU.cpp
+++ b/desmume/src/MMU.cpp
@@ -1802,6 +1802,8 @@ static void writereg_POWCNT1(const int size, const u32 adr, const u32 val) {
 		writereg_POWCNT1(8,adr+1,(val>>8)&0xFF);
 		break;
 	}
+	//do we need to test this?
+	//gbatek: "When disabled, corresponding Ports become Read-only, corresponding (palette-) memory becomes read-only-zero-filled."
 }
 
 static INLINE void MMU_IPCSync(u8 proc, u32 val)
@@ -3224,9 +3226,9 @@ void FASTCALL _MMU_ARM9_write08(u32 adr, u8 val)
 				if ((adr >= 0x04000008) && (adr <= 0x0400005F)) return;
 			if (nds.power1.gpuSub == 0)
 				if ((adr >= 0x04001008) && (adr <= 0x0400105F)) return;
-			if (nds.power1.gfx3d_geometry == 0)
+			if (nds.power_geometry == 0)
 				if ((adr >= 0x04000400) && (adr <= 0x040006FF)) return;
-			if (nds.power1.gfx3d_render == 0)
+			if (nds.power_render == 0)
 				if ((adr >= 0x04000320) && (adr <= 0x040003FF)) return;
 			
 			if(MMU_new.is_dma(adr)) { 
@@ -3708,9 +3710,9 @@ void FASTCALL _MMU_ARM9_write16(u32 adr, u16 val)
 				if ((adr >= 0x04000008) && (adr <= 0x0400005F)) return;
 			if (nds.power1.gpuSub == 0)
 				if ((adr >= 0x04001008) && (adr <= 0x0400105F)) return;
-			if (nds.power1.gfx3d_geometry == 0)
+			if (nds.power_geometry == 0)
 				if ((adr >= 0x04000400) && (adr <= 0x040006FF)) return;
-			if (nds.power1.gfx3d_render == 0)
+			if (nds.power_render == 0)
 				if ((adr >= 0x04000320) && (adr <= 0x040003FF)) return;
 			
 			if(MMU_new.is_dma(adr)) { 
@@ -4288,16 +4290,18 @@ void FASTCALL _MMU_ARM9_write32(u32 adr, u32 val)
 		{
 			if (!validateIORegsWrite<ARMCPU_ARM9>(adr, 32, val)) return;
 			
+			//this blocks writes to memories when the engines that control them are powered down
+			//but is there any other way to write to the geometry engine? (via FIFO?)
 			// TODO: add pal reg
 			if (nds.power1.gpuMain == 0)
 				if ((adr >= 0x04000008) && (adr <= 0x0400005F)) return;
 			if (nds.power1.gpuSub == 0)
 				if ((adr >= 0x04001008) && (adr <= 0x0400105F)) return;
-			if (nds.power1.gfx3d_geometry == 0)
+			if (nds.power_geometry == 0)
 				if ((adr >= 0x04000400) && (adr <= 0x040006FF)) return;
-			if (nds.power1.gfx3d_render == 0)
+			if (nds.power_render == 0)
 				if ((adr >= 0x04000320) && (adr <= 0x040003FF)) return;
-			
+
 			// MightyMax: no need to do several ifs, when only one can happen
 			// switch/case instead
 			// both comparison >=,< per if can be replaced by one bit comparison since
diff --git a/desmume/src/NDSSystem.cpp b/desmume/src/NDSSystem.cpp
index e595d6cfa..c1a769373 100644
--- a/desmume/src/NDSSystem.cpp
+++ b/desmume/src/NDSSystem.cpp
@@ -2533,7 +2533,8 @@ void NDS_Reset()
 	nds.sleeping = FALSE;
 	nds.cardEjected = FALSE;
 	nds.freezeBus = 0;
-	nds.power1.lcd = nds.power1.gpuMain = nds.power1.gfx3d_render = nds.power1.gfx3d_geometry = nds.power1.gpuSub = nds.power1.dispswap = 1;
+	nds.power1.lcd = nds.power1.gpuMain = nds.power1.gfx3d_render = nds.power1.gfx3d_geometry = nds.power1.gpuSub = nds.power1.dispswap = 1; //is this proper?
+	nds.power_geometry = nds.power_render = TRUE; //whether this is proper follows from prior
 	nds.power2.speakers = 1;
 	nds.power2.wifi = 0;
 	nds.wifiCycle = 0;
diff --git a/desmume/src/NDSSystem.h b/desmume/src/NDSSystem.h
index a39739d51..f4ad4c6cc 100644
--- a/desmume/src/NDSSystem.h
+++ b/desmume/src/NDSSystem.h
@@ -238,6 +238,8 @@ struct NDSSystem
 		u8 speakers, wifi /*(initial value=0)*/;
 	} power2; //POWCNT2
 
+	BOOL power_render, power_geometry;
+
 	bool isInVblank() const { return VCount >= 192; } 
 	bool isIn3dVblank() const { return VCount >= 192 && VCount<215; } 
 };
diff --git a/desmume/src/gfx3d.cpp b/desmume/src/gfx3d.cpp
index 80d52d732..232ba4705 100644
--- a/desmume/src/gfx3d.cpp
+++ b/desmume/src/gfx3d.cpp
@@ -401,7 +401,6 @@ static void twiddleLists()
 	vertlist->count = 0;
 }
 
-static BOOL flushPending = FALSE;
 static BOOL drawPending = FALSE;
 //------------------------------------------------------------
 
@@ -549,7 +548,6 @@ void gfx3d_reset()
 	gxf_hardware.reset();
 
 	drawPending = FALSE;
-	flushPending = FALSE;
 	memset(polylists, 0, sizeof(POLYLIST)*2);
 	memset(vertlists, 0, sizeof(VERTLIST)*2);
 	gfx3d.state.invalidateToon = true;
@@ -1781,11 +1779,6 @@ void gfx3d_glClearDepth(u32 v)
 	gfx3d.state.clearDepth = DS_DEPTH15TO24(v);
 }
 
-// Ignored for now
-void gfx3d_glSwapScreen(unsigned int screen)
-{
-}
-
 int gfx3d_GetNumPolys()
 {
 	//so is this in the currently-displayed or currently-built list?
@@ -2335,16 +2328,36 @@ void gfx3d_VBlankEndSignal(bool skipFrame)
 		CurrentRenderer->SetRenderNeedsFinish(false);
 		GPU->GetEventHandler()->DidRender3DEnd();
 	}
+
+	//try powering on geometry
+	if(!nds.power_geometry && nds.power1.gfx3d_geometry)
+	{
+		nds.power_geometry = TRUE;
+	}
+	else if(nds.power_geometry && !nds.power1.gfx3d_geometry)
+	{
+		//kill the geometry data when the power goes off
+		reconstruct(&gfx3d.state);
+		nds.power_geometry = FALSE;
+	}
+
+	//try powering on rendering. unclear whether there's anything very special about this
+	if(!nds.power_render && nds.power1.gfx3d_render)
+		nds.power_render = TRUE;
+	else if(nds.power_render && !nds.power1.gfx3d_render)
+		nds.power_render = FALSE;
+	
 	
 	if (!drawPending) return;
 	if (skipFrame) return;
-	
+
 	drawPending = FALSE;
-	
+
 	GPU->GetEventHandler()->DidRender3DBegin();
 	CurrentRenderer->SetRenderNeedsFinish(true);
 	
-	if (CommonSettings.showGpu.main)
+	//the timing of powering on rendering may not be exactly right here.
+	if (CommonSettings.showGpu.main && nds.power_render)
 	{
 		CurrentRenderer->SetTextureProcessingProperties(CommonSettings.GFX3D_Renderer_TextureScalingFactor,
 														CommonSettings.GFX3D_Renderer_TextureDeposterize,
@@ -2514,7 +2527,6 @@ SFORMAT SF_GFX3D[]={
 	{ "GMAM", 2, 1, &dsAmbient},
 	{ "GMSP", 2, 1, &dsSpecular},
 	{ "GMEM", 2, 1, &dsEmission},
-	{ "GFLP", 4, 1, &flushPending},
 	{ "GDRP", 4, 1, &drawPending},
 	{ "GSET", 4, 1, &gfx3d.state.enableTexturing},
 	{ "GSEA", 4, 1, &gfx3d.state.enableAlphaTest},
diff --git a/desmume/src/saves.cpp b/desmume/src/saves.cpp
index 4333b002f..77bc99362 100644
--- a/desmume/src/saves.cpp
+++ b/desmume/src/saves.cpp
@@ -213,6 +213,8 @@ SFORMAT SF_NDS[]={
 	{ "_P05", 1, 1, &nds.power1.dispswap},
 	{ "_P06", 1, 1, &nds.power2.speakers},
 	{ "_P07", 1, 1, &nds.power2.wifi},
+	{ "_P0G", 1, 1, &nds.power_geometry},
+	{ "_P0R", 1, 1, &nds.power_render},
 	{ 0 }
 };