diff --git a/src/display/pspdisplay.h b/src/display/pspdisplay.h
index c72ca31d..2e31f08e 100644
--- a/src/display/pspdisplay.h
+++ b/src/display/pspdisplay.h
@@ -31,12 +31,15 @@ enum PspDisplayPixelFormats {
 };
 
 enum PspDisplaySetBufSync {
-	/** Buffer change effective immediately */
-	PSP_DISPLAY_SETBUF_IMMEDIATE = 0,
-	/** Buffer change effective next frame */
-	PSP_DISPLAY_SETBUF_NEXTFRAME = 1
+	/** Buffer change effective next hsync */
+	PSP_DISPLAY_SETBUF_NEXTHSYNC = 0,
+	/** Buffer change effective next vsync */
+	PSP_DISPLAY_SETBUF_NEXTVSYNC = 1
 };
 
+/** Values for retro compatibility */
+#define PSP_DISPLAY_SETBUF_IMMEDIATE PSP_DISPLAY_SETBUF_NEXTHSYNC
+#define PSP_DISPLAY_SETBUF_NEXTFRAME PSP_DISPLAY_SETBUF_NEXTVSYNC
 
 enum PspDisplayErrorCodes
 {
diff --git a/src/gu/Makefile.am b/src/gu/Makefile.am
index c0cb0145..1a44d0cb 100644
--- a/src/gu/Makefile.am
+++ b/src/gu/Makefile.am
@@ -57,6 +57,7 @@ libpspgu_a_SOURCES = \
 	sceGuEnable.c \
 	sceGuEndObject.c \
 	sceGuFinish.c \
+	sceGuFinishId.c \
 	sceGuFog.c \
 	sceGuFrontFace.c \
 	sceGuGetAllStatus.c \
diff --git a/src/gu/guInternal.h b/src/gu/guInternal.h
index 8c3b5eb2..0b214dd9 100644
--- a/src/gu/guInternal.h
+++ b/src/gu/guInternal.h
@@ -116,7 +116,7 @@ extern GuLightSettings light_settings[4];
 
 void callbackSig(int id, void *arg);
 void callbackFin(int id, void *arg);
-void resetValues();
+void _sceGuResetGlobalVariables();
 
 typedef enum GECommand
 {
@@ -645,12 +645,18 @@ static inline void sendCommandf(GECommand cmd, float argument)
 	sendCommandi(cmd, t.i >> 8);
 }
 
-static inline void sendCommandiStall(GECommand cmd, int argument)
-{
-	sendCommandi(cmd, argument);
-
-	if (!gu_object_stack_depth && !gu_curr_context)
-		sceGeListUpdateStallAddr(ge_list_executed[0], gu_list->current);
+static inline int _sceGuUpdateStallAddr(void) {
+	if (gu_curr_context == GU_DIRECT) {
+		// Just if there are no objects in the stack (no guBeginObject)
+		if (!gu_object_stack_depth) {
+			int res;
+			res = sceGeListUpdateStallAddr(ge_list_executed[0], gu_list->current);
+			if (res < 0) {
+				return res;
+			}
+		}
+	} 
+	return 0;
 }
 
 #endif
diff --git a/src/gu/pspgu.h b/src/gu/pspgu.h
index c5f246fb..bd185dfc 100644
--- a/src/gu/pspgu.h
+++ b/src/gu/pspgu.h
@@ -433,8 +433,10 @@ void sceGuFog(float near, float far, unsigned int color);
   * Initalize the GU system
   *
   * This function MUST be called as the first function, otherwise state is undetermined.
+  *
+  * @return 0 for success, < 0 for failure
 **/
-void sceGuInit(void);
+int sceGuInit(void);
 
 /**
   * Shutdown the GU system
@@ -475,6 +477,11 @@ void* sceGuSetCallback(int signal, void (*callback)(int));
 
 /**
   * Trigger signal to call code from the command stream
+  * 
+  * Available signals are:
+  *   - GU_SIGNAL_WAIT - Wait for callback to finish
+  *   - GU_SIGNAL_NOWAIT - Do not wait for callback to finish
+  *   - GU_SIGNAL_PAUSE - Pause execution until callback is finished
   *
   * Available behaviors are:
   *   - GU_BEHAVIOR_SUSPEND - Stops display list execution until callback function finished
@@ -564,8 +571,9 @@ int sceGuFinishId(unsigned int id);
   * Call previously generated display-list
   *
   * @param list - Display list to call
+  * @return 0 for success, < 0 for failure
 **/
-void sceGuCallList(const void* list);
+int sceGuCallList(const void* list);
 
 /**
   * Set wether to use stack-based calls or signals to handle execution of called lists.
@@ -1525,8 +1533,8 @@ void sceGuDrawArrayN(int primitive_type, int vertex_type, int vcount, int primco
   * Set how the display should be set
   *
   * Available behaviours are:
-  *   - PSP_DISPLAY_SETBUF_IMMEDIATE - Display is swapped immediately
-  *   - PSP_DISPLAY_SETBUF_NEXTFRAME - Display is swapped on the next frame
+  *   - PSP_DISPLAY_SETBUF_NEXTHSYNC - Display is swapped on the next hsync
+  *   - PSP_DISPLAY_SETBUF_NEXTVSYNC - Display is swapped on the next vsync
   *
   * Do remember that this swaps the pointers internally, regardless of setting, so be careful to wait until the next
   * vertical blank or use another buffering algorithm (see guSwapBuffersCallback()).
diff --git a/src/gu/resetValues.c b/src/gu/resetValues.c
index 2b039533..4fed2744 100644
--- a/src/gu/resetValues.c
+++ b/src/gu/resetValues.c
@@ -8,7 +8,7 @@
 
 #include "guInternal.h"
 
-void resetValues()
+void _sceGuResetGlobalVariables()
 {
 	unsigned int i;
 
@@ -18,7 +18,7 @@ void resetValues()
 	gu_current_frame = 0;
 	gu_object_stack_depth = 0;
 
-	gu_display_on = 0;
+	gu_display_on = GU_FALSE;
 	gu_call_mode = GU_CALL_NORMAL;
 
 	gu_draw_buffer.pixel_size = 1;
diff --git a/src/gu/sceGuCallList.c b/src/gu/sceGuCallList.c
index d59043ad..20a4bb0c 100644
--- a/src/gu/sceGuCallList.c
+++ b/src/gu/sceGuCallList.c
@@ -8,19 +8,25 @@
 
 #include "guInternal.h"
 
-void sceGuCallList(const void *list)
+int sceGuCallList(const void *list)
 {
+	int res;
 	unsigned int list_addr = (unsigned int)list;
 
 	if (gu_call_mode == GU_CALL_SIGNAL)
 	{
 		sendCommandi(SIGNAL, (list_addr >> 16) | 0x110000);
 		sendCommandi(END, list_addr & 0xffff);
-		sendCommandiStall(NOP, 0);
 	}
 	else
 	{
 		sendCommandi(BASE, (list_addr >> 8) & 0xf0000);
-		sendCommandiStall(CALL, list_addr);
+		sendCommandi(CALL, list_addr);
 	}
+
+	res = _sceGuUpdateStallAddr();
+	if (res < 0) {
+		return res;
+	}
+	return 0;
 }
diff --git a/src/gu/sceGuColor.c b/src/gu/sceGuColor.c
index 4ccc4549..946bd39e 100644
--- a/src/gu/sceGuColor.c
+++ b/src/gu/sceGuColor.c
@@ -10,5 +10,5 @@
 
 void sceGuColor(unsigned int color)
 {
-	sceGuMaterial(7,color);
+	sceGuMaterial(GU_AMBIENT | GU_DIFFUSE | GU_SPECULAR, color);
 }
diff --git a/src/gu/sceGuDisable.c b/src/gu/sceGuDisable.c
index 461fbf5b..8b05eaad 100644
--- a/src/gu/sceGuDisable.c
+++ b/src/gu/sceGuDisable.c
@@ -89,6 +89,6 @@ void sceGuDisable(int state)
 	break;
 	}
 
-	if (state < 22)
+	if (state < GU_MAX_STATUS)
 		gu_states &= ~(1 << state);
 }
diff --git a/src/gu/sceGuDispBuffer.c b/src/gu/sceGuDispBuffer.c
index 0436522e..807c1d41 100644
--- a/src/gu/sceGuDispBuffer.c
+++ b/src/gu/sceGuDispBuffer.c
@@ -30,5 +30,5 @@ void sceGuDispBuffer(int width, int height, void *dispbp, int dispbw)
 	sceDisplaySetMode(0, gu_draw_buffer.width, gu_draw_buffer.height);
 
 	if (gu_display_on)
-		sceDisplaySetFrameBuf((void *)(((unsigned int)ge_edram_address) + ((unsigned int)gu_draw_buffer.disp_buffer)), dispbw, gu_draw_buffer.pixel_size, PSP_DISPLAY_SETBUF_NEXTFRAME);
+		sceDisplaySetFrameBuf((void *)(((unsigned int)ge_edram_address) + ((unsigned int)gu_draw_buffer.disp_buffer)), dispbw, gu_draw_buffer.pixel_size, PSP_DISPLAY_SETBUF_NEXTVSYNC);
 }
diff --git a/src/gu/sceGuDisplay.c b/src/gu/sceGuDisplay.c
index 6006c524..90987c4e 100644
--- a/src/gu/sceGuDisplay.c
+++ b/src/gu/sceGuDisplay.c
@@ -13,10 +13,10 @@
 
 int sceGuDisplay(int state)
 {
-	if (state)
-		sceDisplaySetFrameBuf((void*)((unsigned int)ge_edram_address+(unsigned int)gu_draw_buffer.disp_buffer),gu_draw_buffer.frame_width,gu_draw_buffer.pixel_size,PSP_DISPLAY_SETBUF_NEXTFRAME);
+	if (state == GU_TRUE)
+		sceDisplaySetFrameBuf((void *)((unsigned int)ge_edram_address + (unsigned int)gu_draw_buffer.disp_buffer), gu_draw_buffer.frame_width, gu_draw_buffer.pixel_size, PSP_DISPLAY_SETBUF_NEXTVSYNC);
 	else
-		sceDisplaySetFrameBuf(0,0,0,PSP_DISPLAY_SETBUF_NEXTFRAME);
+		sceDisplaySetFrameBuf(NULL, 0, 0, PSP_DISPLAY_SETBUF_NEXTVSYNC);
 
 	gu_display_on = state;
 	return state;
diff --git a/src/gu/sceGuDrawArray.c b/src/gu/sceGuDrawArray.c
index c98143c9..2dcdb872 100644
--- a/src/gu/sceGuDrawArray.c
+++ b/src/gu/sceGuDrawArray.c
@@ -25,5 +25,6 @@ void sceGuDrawArray(int prim, int vtype, int count, const void *indices, const v
     sendCommandi(VADDR, ((unsigned int)vertices));
   }
 
-  sendCommandiStall(PRIM, (prim << 16) | count);
+  sendCommandi(PRIM, (prim << 16) | count);
+  _sceGuUpdateStallAddr();
 }
diff --git a/src/gu/sceGuDrawArrayN.c b/src/gu/sceGuDrawArrayN.c
index 7bf743f5..dd5ecc45 100644
--- a/src/gu/sceGuDrawArrayN.c
+++ b/src/gu/sceGuDrawArrayN.c
@@ -30,7 +30,7 @@ void sceGuDrawArrayN(int primitive_type, int vertex_type, int vcount, int primco
 		int i;
 		for (i = 0; i < primcount; i++)
 			sendCommandi(PRIM, (primitive_type << 16) | vcount);
-
-		sendCommandiStall(PRIM, (primitive_type << 16) | vcount);
 	}
+
+	_sceGuUpdateStallAddr();
 }
diff --git a/src/gu/sceGuEnable.c b/src/gu/sceGuEnable.c
index ad6d38de..770752b3 100644
--- a/src/gu/sceGuEnable.c
+++ b/src/gu/sceGuEnable.c
@@ -89,6 +89,6 @@ void sceGuEnable(int state)
 	break;
 	}
 
-	if (state < 22)
+	if (state < GU_MAX_STATUS)
 		gu_states |= (1 << state);
 }
diff --git a/src/gu/sceGuFinish.c b/src/gu/sceGuFinish.c
index 9f68aadd..ad03b7f1 100644
--- a/src/gu/sceGuFinish.c
+++ b/src/gu/sceGuFinish.c
@@ -8,42 +8,6 @@
 
 #include "guInternal.h"
 
-int sceGuFinishId(unsigned int id)
-{
-	switch (gu_curr_context)
-	{
-	case GU_DIRECT:
-	case GU_SEND:
-	{
-		sendCommandi(FINISH, id & 0xffff);
-		sendCommandiStall(END, 0);
-	}
-	break;
-
-	case GU_CALL:
-	{
-		if (gu_call_mode == GU_CALL_SIGNAL)
-		{
-			sendCommandi(SIGNAL, 0x120000);
-			sendCommandi(END, 0);
-			sendCommandiStall(NOP, 0);
-		}
-		else
-		{
-			sendCommandi(RET, 0);
-		}
-	}
-	break;
-	}
-
-	unsigned int size = ((unsigned int)gu_list->current) - ((unsigned int)gu_list->start);
-
-	// go to parent list
-	gu_curr_context = gu_list->parent_context;
-	gu_list = &gu_contexts[gu_curr_context].list;
-	return size;
-}
-
 int sceGuFinish(void)
 {
 	return sceGuFinishId(0);
diff --git a/src/gu/sceGuFinishId.c b/src/gu/sceGuFinishId.c
new file mode 100644
index 00000000..ad5e638f
--- /dev/null
+++ b/src/gu/sceGuFinishId.c
@@ -0,0 +1,56 @@
+/*
+ * PSP Software Development Kit - https://github.com/pspdev
+ * -----------------------------------------------------------------------
+ * Licensed under the BSD license, see LICENSE in PSPSDK root for details.
+ *
+ * Copyright (c) 2005 Jesper Svennevid
+ */
+
+#include "guInternal.h"
+#include <pspdisplay.h>
+#include <pspuser.h>
+
+int sceGuFinishId(unsigned int id)
+{
+	int ret;
+	int intr;
+
+	switch (gu_curr_context)
+	{
+	case GU_DIRECT:
+		sendCommandi(FINISH, id & 0xffff);
+		sendCommandi(END, 0);
+		ret = _sceGuUpdateStallAddr();
+		if (ret < 0)
+		{
+			return ret;
+		}
+		break;
+	case GU_SEND:
+		sendCommandi(FINISH, id & 0xffff);
+		sendCommandi(END, 0);
+		break;
+	case GU_CALL:
+		if (gu_call_mode == GU_CALL_SIGNAL)
+		{
+			sendCommandi(SIGNAL, 0x120000);
+			sendCommandi(END, 0);
+		}
+		else
+		{
+			sendCommandi(RET, 0);
+		}
+		break;
+	default:
+		return SCE_DISPLAY_ERROR_ARGUMENT;
+	}
+
+	unsigned int size = ((unsigned int)gu_list->current) - ((unsigned int)gu_list->start);
+
+	// go to parent list
+	intr = sceKernelCpuSuspendIntr();
+	gu_curr_context = gu_list->parent_context;
+	gu_list = &gu_contexts[gu_curr_context].list;
+	sceKernelCpuResumeIntr(intr);
+	return size;
+}
\ No newline at end of file
diff --git a/src/gu/sceGuInit.c b/src/gu/sceGuInit.c
index 46a428f8..8a51ae80 100644
--- a/src/gu/sceGuInit.c
+++ b/src/gu/sceGuInit.c
@@ -235,46 +235,70 @@ static unsigned int __attribute__((aligned(16))) ge_init_list[] =
 	ZV(END),
 };
 
-void callbackFin(int id, void* arg)
+void callbackFin(int id, void *arg)
 {
-	GuSettings* settings = (GuSettings*)arg;
+	GuSettings *settings = (GuSettings *)arg;
 	if (settings->fin)
 		settings->fin(id & 0xffff);
 }
 
-void callbackSig(int id, void* arg)
+void callbackSig(int id, void *arg)
 {
-	GuSettings* settings = (GuSettings*)arg;
+	GuSettings *settings = (GuSettings *)arg;
 
 	settings->signal_history[(settings->signal_offset++) & 15] = id & 0xffff;
 
 	if (settings->sig)
 		settings->sig(id & 0xffff);
 
-	sceKernelSetEventFlag(settings->kernel_event_flag,1);
+	sceKernelSetEventFlag(settings->kernel_event_flag, 1);
 }
 
-void sceGuInit(void)
+int sceGuInit(void)
 {
+	int res;
 	PspGeCallbackData callback;
+
+	ge_edram_address = sceGeEdramGetAddr();
+	_sceGuResetGlobalVariables();
+
+	res = sceKernelCreateEventFlag("SceGuSignal", PSP_EVENT_WAITMULTIPLE, 3, 0);
+	if (res < 0)
+	{
+		return res;
+	}
+	gu_settings.kernel_event_flag = res;
+
 	callback.signal_func = callbackSig;
 	callback.signal_arg = &gu_settings;
 	callback.finish_func = callbackFin;
 	callback.finish_arg = &gu_settings;
-	gu_settings.ge_callback_id = sceGeSetCallback(&callback);
-
-	gu_settings.swapBuffersCallback = 0;
-	gu_settings.swapBuffersBehaviour = PSP_DISPLAY_SETBUF_IMMEDIATE;
-
-	ge_edram_address = sceGeEdramGetAddr();
+	res = sceGeSetCallback(&callback);
+	if (res < 0)
+	{
+		sceKernelDeleteEventFlag(gu_settings.kernel_event_flag);
+		gu_settings.kernel_event_flag = -1;
+		return res;
+	}
+	gu_settings.ge_callback_id = res;
 
 	// initialize graphics hardware
-	ge_list_executed[0] = sceGeListEnQueue((void *)((unsigned int)ge_init_list & 0x1fffffff), 0, gu_settings.ge_callback_id, 0);
-
-	resetValues();
-
-	gu_settings.kernel_event_flag = sceKernelCreateEventFlag("SceGuSignal", 512, 3, 0);
-
+	res = sceGeListEnQueue((void *)((unsigned int)ge_init_list & 0x1fffffff), NULL, gu_settings.ge_callback_id, NULL);
+	if (res < 0)
+	{
+		sceKernelDeleteEventFlag(gu_settings.kernel_event_flag);
+		sceGeUnsetCallback(gu_settings.ge_callback_id);
+		gu_settings.ge_callback_id = -1;
+		gu_settings.kernel_event_flag = -1;
+		return res;
+	}
+	ge_list_executed[0] = res;
 	// wait for init to complete
 	sceGeListSync(ge_list_executed[0], 0);
+	sceGeDrawSync(0);
+
+	gu_settings.swapBuffersCallback = NULL;
+	gu_settings.swapBuffersBehaviour = PSP_DISPLAY_SETBUF_NEXTHSYNC;
+
+	return 0;
 }
diff --git a/src/gu/sceGuSendList.c b/src/gu/sceGuSendList.c
index 41ad460e..71b781b5 100644
--- a/src/gu/sceGuSendList.c
+++ b/src/gu/sceGuSendList.c
@@ -13,15 +13,18 @@
 
 int sceGuSendList(int mode, const void *list, PspGeContext *context)
 {
-	gu_settings.signal_offset = 0;
-
-	// TODO: figure out this structure
 	PspGeListArgs args;
-	args.size = 8; // Size of structure?
-	args.context = context;
+	int list_id;
+	int callback;
 
-	int list_id = 0;
-	int callback = gu_settings.ge_callback_id;
+	args.size = sizeof(PspGeListArgs);
+	args.context = context;
+	args.numStacks = 0;
+	args.stacks = NULL;
+
+	callback = gu_settings.ge_callback_id;
+	gu_settings.signal_offset = 0;
+	list_id = -1;
 
 	switch (mode)
 	{
diff --git a/src/gu/sceGuSetCallback.c b/src/gu/sceGuSetCallback.c
index e101a46e..e75607ab 100644
--- a/src/gu/sceGuSetCallback.c
+++ b/src/gu/sceGuSetCallback.c
@@ -8,24 +8,19 @@
 
 #include "guInternal.h"
 
-void* sceGuSetCallback(int signal, GuCallback callback)
+void *sceGuSetCallback(int signal, GuCallback callback)
 {
-	GuCallback old_callback = 0;
+	GuCallback old_callback = NULL;
 
 	switch (signal)
 	{
-		case GU_CALLBACK_SIGNAL:
-		{
-			old_callback = gu_settings.sig;
-			gu_settings.sig = callback;
-		}
+	case GU_CALLBACK_SIGNAL:
+		old_callback = gu_settings.sig;
+		gu_settings.sig = callback;
 		break;
-
-		case GU_CALLBACK_FINISH:
-		{
-			old_callback = gu_settings.fin;
-			gu_settings.fin = callback;
-		}
+	case GU_CALLBACK_FINISH:
+		old_callback = gu_settings.fin;
+		gu_settings.fin = callback;
 		break;
 	}
 
diff --git a/src/gu/sceGuShadeModel.c b/src/gu/sceGuShadeModel.c
index 35808603..faef3007 100644
--- a/src/gu/sceGuShadeModel.c
+++ b/src/gu/sceGuShadeModel.c
@@ -10,5 +10,5 @@
 
 void sceGuShadeModel(int mode)
 {
-	sendCommandi(SHADE_MODE, mode ? 1 : 0);
+	sendCommandi(SHADE_MODE, mode);
 }
diff --git a/src/gu/sceGuSignal.c b/src/gu/sceGuSignal.c
index c1779c16..df691cc0 100644
--- a/src/gu/sceGuSignal.c
+++ b/src/gu/sceGuSignal.c
@@ -13,11 +13,11 @@ void sceGuSignal(int signal, int argument)
 	sendCommandi(SIGNAL, ((signal & 0xff) << 16) | (argument & 0xffff));
 	sendCommandi(END, 0);
 
-	if (GU_SIGNAL_PAUSE == 3)
+	if (signal == GU_SIGNAL_PAUSE)
 	{
 		sendCommandi(FINISH, 0);
 		sendCommandi(END, 0);
 	}
 
-	sendCommandiStall(NOP, 0);
-}
+	_sceGuUpdateStallAddr();
+}
\ No newline at end of file
diff --git a/src/gu/sceGuStart.c b/src/gu/sceGuStart.c
index ef14da39..96791e9a 100644
--- a/src/gu/sceGuStart.c
+++ b/src/gu/sceGuStart.c
@@ -10,12 +10,16 @@
 
 #include <pspkernel.h>
 #include <pspge.h>
+#include <pspuser.h>
 
 void sceGuStart(int ctype, void *list)
 {
+	int intr;
 	GuContext *context = &gu_contexts[ctype];
 	unsigned int *local_list = (unsigned int *)(((unsigned int)list) | 0x40000000);
 
+	intr = sceKernelCpuSuspendIntr();
+
 	// setup display list
 
 	context->list.start = local_list;
@@ -26,10 +30,11 @@ void sceGuStart(int ctype, void *list)
 	// store current context
 
 	gu_curr_context = ctype;
+	sceKernelCpuResumeIntr(intr);
 
 	if (ctype == GU_DIRECT)
 	{
-		ge_list_executed[0] = sceGeListEnQueue(local_list, local_list, gu_settings.ge_callback_id, 0);
+		ge_list_executed[0] = sceGeListEnQueue(local_list, local_list, gu_settings.ge_callback_id, NULL);
 		gu_settings.signal_offset = 0;
 	}
 
diff --git a/src/gu/sceGuSync.c b/src/gu/sceGuSync.c
index ffd77acd..d23a753f 100644
--- a/src/gu/sceGuSync.c
+++ b/src/gu/sceGuSync.c
@@ -15,9 +15,15 @@ int sceGuSync(int mode, int what)
 {
 	switch (mode)
 	{
-		case GU_SYNC_FINISH: return sceGeDrawSync(what);
-		case GU_SYNC_LIST: return sceGeListSync(ge_list_executed[0],what);
-		case GU_SYNC_SEND: return sceGeListSync(ge_list_executed[1],what);
-		default: case GU_SYNC_SIGNAL: case GU_SYNC_DONE: return 0;
+	case GU_SYNC_FINISH:
+		return sceGeDrawSync(what);
+	case GU_SYNC_LIST:
+		return sceGeListSync(ge_list_executed[0], what);
+	case GU_SYNC_SEND:
+		return sceGeListSync(ge_list_executed[1], what);
+	default:
+	case GU_SYNC_SIGNAL:
+	case GU_SYNC_DONE:
+		return 0;
 	}
 }
diff --git a/src/samples/prx/image_display/main.c b/src/samples/prx/image_display/main.c
index 82aedf6b..260bfe3b 100644
--- a/src/samples/prx/image_display/main.c
+++ b/src/samples/prx/image_display/main.c
@@ -129,8 +129,8 @@ int main_thread(SceSize args, void *argp){
 		
 		
 		// get vram
-		int ret = sceDisplayGetFrameBuf((void*)&vram32, &bufferwidth, &pixelformat, PSP_DISPLAY_SETBUF_IMMEDIATE); 
-		// works with both PSP_DISPLAY_SETBUF_NEXTFRAME and PSP_DISPLAY_SETBUF_IMMEDIATE
+		int ret = sceDisplayGetFrameBuf((void*)&vram32, &bufferwidth, &pixelformat, PSP_DISPLAY_SETBUF_NEXTHSYNC); 
+		// works with both PSP_DISPLAY_SETBUF_NEXTVSYNC and PSP_DISPLAY_SETBUF_NEXTHSYNC
 		
 		// check if return value from sceDisplayGetFrameBuf is valid
 		// check if vram32 is not NULL
diff --git a/src/user/pspthreadman.h b/src/user/pspthreadman.h
index 8fe7b350..60ff9126 100644
--- a/src/user/pspthreadman.h
+++ b/src/user/pspthreadman.h
@@ -690,6 +690,8 @@ typedef struct SceKernelEventFlagOptParam SceKernelEventFlagOptParam;
 /** Event flag creation attributes */
 enum PspEventFlagAttributes
 {
+	/** Allow the event flag to be waited upon by a single thread */
+	PSP_EVENT_WAITSINGLE = 0x00,
 	/** Allow the event flag to be waited upon by multiple threads */
 	PSP_EVENT_WAITMULTIPLE = 0x200
 };