diff --git a/config/rel_slices.yml b/config/rel_slices.yml
index d1feff66..aea07383 100644
--- a/config/rel_slices.yml
+++ b/config/rel_slices.yml
@@ -6,6 +6,10 @@ m_debug_hayakawa.c:
     .text: [0x803965E4, 0x803973E8]
     .rodata: [0x80641D50, 0x80641D90]
     .data: [0x80651328, 0x80651358]
+m_fbdemo.c:
+    .text: [0x803A0350, 0x803A0ABC]
+    .rodata: [0x80641F40, 0x80641F60]
+    .data: [0x80652AA0, 0x80652AD0]
 m_huusui_room.c:
     .text: [0x803B1908, 0x803B1968]
 m_home.c:
diff --git a/include/libc64/sleep.h b/include/libc64/sleep.h
new file mode 100644
index 00000000..68e6a0c4
--- /dev/null
+++ b/include/libc64/sleep.h
@@ -0,0 +1,9 @@
+#ifndef SLEEP_H
+#define SLEEP_H
+
+#include "types.h"
+#include "dolphin/os/OSTime.h"
+
+void csleep(OSTime c);
+void msleep(int);
+#endif
\ No newline at end of file
diff --git a/include/libultra/gu.h b/include/libultra/gu.h
index 5ce54ee7..0e7fe7ef 100644
--- a/include/libultra/gu.h
+++ b/include/libultra/gu.h
@@ -4,6 +4,7 @@
 #include "types.h"
 #include "libultra/ultratypes.h"
 
+void guMtxIdentF(float mf[4][4]);
 
 inline void guTranslateF(float m[4][4], float x, float y, float z){
     guMtxIdentF(m);
@@ -21,7 +22,7 @@ inline void guScaleF(float mf[4][4], float x, float y, float z) {
 }
 
 void guMtxF2L(float mf[4][4], Mtx *m);
-void guMtxIdentF(float mf[4][4]);
+
 void guTranslate(Mtx *m, float x, float y, float z);
 void guScale(Mtx *m, float x, float y, float z);
 
diff --git a/include/m_fbdemo.h b/include/m_fbdemo.h
new file mode 100644
index 00000000..c9e1a5c7
--- /dev/null
+++ b/include/m_fbdemo.h
@@ -0,0 +1,36 @@
+#ifndef FBDEMO_H
+#define FBDEMO_H
+
+#include "types.h"
+#include "PR/mbi.h"
+
+typedef struct {
+    /* 0x0 */ f32 x;
+    /* 0x4 */ f32 y;
+} TransitionTileVtxData; // size = 0x8
+
+typedef struct {
+    /* 0x00 */ int cols;
+    /* 0x04 */ int rows;
+    /* 0x08 */ int frame;
+    /* 0x0C */ TransitionTileVtxData* vtxData;
+    /* 0x10 */ Vtx* vtxFrame1;
+    /* 0x14 */ Vtx* vtxFrame2;
+    /* 0x18 */ Mtx projection;
+    /* 0x58 */ Mtx modelView;
+    /* 0x98 */ Mtx unk_98;
+    /* 0xD8 */ Gfx* gfx; // "gfxtbl"
+    /* 0xDC */ u16* zBuffer;
+} TransitionTile; // size = 0xE0
+
+
+extern void fbdemo_init_gfx(TransitionTile*);
+extern void fbdemo_init_data(TransitionTile*);
+extern void fbdemo_cleanup(TransitionTile*);
+extern TransitionTile* fbdemo_init(TransitionTile*, int, int); 
+extern void fbdemo_update(TransitionTile*);
+extern void fbdemo_draw(TransitionTile*, Gfx**);
+extern void fbdemo_move(void);
+
+#endif
+
diff --git a/rel/m_fbdemo.c b/rel/m_fbdemo.c
new file mode 100644
index 00000000..e46c7dbe
--- /dev/null
+++ b/rel/m_fbdemo.c
@@ -0,0 +1,204 @@
+#include "m_fbdemo.h"
+#include "libultra/gu.h"
+#include "libc64/malloc.h"
+#include "libc64/sleep.h"
+
+Gfx fbdemo_gfx_init[] ={
+    gsDPPipeSync(),
+    gsSPTexture(0x8000, 0x8000, 0, G_TX_RENDERTILE, G_ON),
+    gsSPClearGeometryMode(G_ZBUFFER | G_SHADE | G_CULL_BOTH | G_FOG | G_LIGHTING | G_TEXTURE_GEN | G_TEXTURE_GEN_LINEAR | G_LOD | G_SHADING_SMOOTH),
+    gsDPSetCombineMode(G_CC_DECALRGB, G_CC_DECALRGB),
+    gsDPSetOtherMode(G_AD_DISABLE | G_CD_MAGICSQ | G_CK_NONE | G_TC_FILT | G_TF_BILERP | G_TT_NONE | G_TL_TILE | G_TD_CLAMP | G_TP_PERSP | G_CYC_1CYCLE | G_PM_1PRIMITIVE, G_AC_NONE | G_ZS_PIXEL | G_RM_AA_OPA_SURF | G_RM_AA_OPA_SURF2),
+    gsSPEndDisplayList(),
+};
+
+extern void fbdemo_init_gfx(TransitionTile* this) {
+    
+    int col;
+    int col2;
+    int colTex;
+    int rowTex;
+    
+    int row;
+    int frame;
+    
+    Vtx* vtx;
+    Gfx* gfx;
+    
+    
+
+    guMtxIdent(&this->modelView);
+    guMtxIdent(&this->unk_98);
+    guOrtho(&this->projection, 0.0f, 320, 240, 0.0f, -1000.0f, 1000.0f, 1.0f);
+
+    for (frame = 0; frame < 2; frame++) {
+        this->frame = frame;
+        vtx = (this->frame == 0) ? this->vtxFrame1 : this->vtxFrame2;
+        for (rowTex = 0, row = 0; row < (this->rows + 1);rowTex += 0x20 ,row++) {
+            for (colTex = 0, col = 0; col < (this->cols + 1); colTex += 0x20, col++) {
+                Vtx_tn* vtxn = &vtx->n;
+                vtx++; 
+                vtxn->ob[0] = col * 0x20; 
+                vtxn->ob[1] = row * 0x20; 
+                vtxn->ob[2] = -5; 
+                vtxn->flag = 0; 
+                vtxn->tc[0] = colTex << 6; 
+                vtxn->tc[1] = rowTex << 6; 
+                vtxn->n[0] = 0; 
+                vtxn->n[1] = 0; 
+                vtxn->n[2] = 120; 
+                vtxn->a = 255;
+            }
+        }
+    }
+
+    gfx = this->gfx;
+    for (rowTex = 0, row = 0; row < this->rows; rowTex += 0x20,row++) {
+        gSPVertex(gfx++, SEGMENT_ADDR(0xA, (u32)row * (this->cols + 1) * sizeof(Vtx)), 2 * (this->cols + 1), 0);
+        
+        colTex = 0;
+        col = 0;
+        col2 = 0;
+        while (col < this->cols) {
+            gDPPipeSync(gfx++);
+
+            gDPLoadTextureTile(gfx++, SEGMENT_ADDR(0xB, 0), G_IM_FMT_RGBA, G_IM_SIZ_16b, 320, 240,
+                               colTex, rowTex, colTex + 0x20, rowTex + 0x20, 0, G_TX_NOMIRROR | G_TX_WRAP,
+                               G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMASK, G_TX_NOMASK, G_TX_NOLOD, G_TX_NOLOD);
+
+            gSP1Quadrangle(gfx++, col2, col2 + 1, + (this->cols) + 2 + col2 , this->cols + 1 + col2, 0);
+
+            colTex += 0x20;
+            col2++;
+            col++;
+        }
+        
+    }
+
+    gDPPipeSync(gfx++);
+    gSPEndDisplayList(gfx++);
+}
+
+extern void fbdemo_init_data(TransitionTile* this) {
+    int col;
+    int row;
+    
+
+    for (row = 0; row < this->rows + 1; row++) {
+        for (col = 0; col < this->cols + 1; col++) {
+            (this->vtxData + col + row * (this->cols + 1))->x = col * 0x20;
+            (this->vtxData + col + row * (this->cols + 1))->y = row * 0x20;
+        }
+    }
+}
+
+extern void fbdemo_cleanup(TransitionTile* this){
+    msleep(100);
+
+    if (this->vtxData != NULL) {
+        free(this->vtxData);
+        this->vtxData = NULL;
+    }
+    if (this->vtxFrame1 != NULL) {
+        free(this->vtxFrame1);
+        this->vtxFrame1 = NULL;
+    }
+    if (this->vtxFrame2 != NULL) {
+        free(this->vtxFrame2);
+        this->vtxFrame2 = NULL;
+    }
+    if (this->gfx != NULL) {
+        free(this->gfx);
+        this->gfx = NULL;
+    }
+}
+
+extern TransitionTile* fbdemo_init(TransitionTile* this, int cols, int rows){
+
+    s32 gridsize;
+    
+    bzero(this, sizeof(TransitionTile));
+
+    this->cols = cols;
+    this->rows = rows;
+    
+    
+    
+    this->frame = 0;
+    this->vtxData = malloc((cols + 1) * sizeof(TransitionTileVtxData) * (rows + 1));
+
+    this->vtxFrame1 = malloc((cols + 1) * sizeof(Vtx) * (rows + 1));
+    this->vtxFrame2 = malloc((cols + 1) * sizeof(Vtx) * (rows + 1));
+
+    this->gfx = malloc(((this->cols * 9 + 1) * this->rows + 2) * sizeof(Gfx));
+
+    if ((this->vtxData == NULL) || (this->vtxFrame1 == NULL) || 
+        (this->vtxFrame2 == NULL) || (this->gfx == NULL)) {
+        
+        if (this->vtxData != NULL) {
+            free(this->vtxData);
+            this->vtxData = NULL;
+        }
+        
+        if (this->vtxFrame1 != NULL) {
+            free(this->vtxFrame1);
+            this->vtxFrame1 = NULL;
+        }
+        
+        if (this->vtxFrame2 != NULL) {
+            free(this->vtxFrame2);
+            this->vtxFrame2 = NULL;
+        }
+        
+        if (this->gfx != NULL) {
+            free(this->gfx);
+            this->gfx = NULL;
+        }
+        
+        return NULL;
+    }
+
+    fbdemo_init_gfx(this);
+    fbdemo_init_data(this);
+    this->frame = 0;
+
+    return this;
+}
+    
+
+extern void fbdemo_update(TransitionTile* this) {
+    int col;
+    int row;
+    Vtx* vtx;
+
+    for (row = 0; row < this->rows + 1; row++) {
+        for (col = 0; col < this->cols + 1; col++) {
+            vtx = (this->frame == 0) ? this->vtxFrame1 : this->vtxFrame2;
+            (vtx + col + row * (this->cols + 1))->n.ob[0] = (this->vtxData + col + row * (this->cols + 1))->x;
+
+            vtx = (this->frame == 0) ? this->vtxFrame1 : this->vtxFrame2;
+            (vtx + col + row * (this->cols + 1))->n.ob[1] = (this->vtxData + col + row * (this->cols + 1))->y;
+        }
+    }
+}
+
+void fbdemo_draw(TransitionTile* this, Gfx** gfxP) {
+    Gfx* gfx = *gfxP;
+
+    gSPDisplayList(gfx++, fbdemo_gfx_init);
+    fbdemo_update(this);
+    gSPMatrix(gfx++, &this->projection, G_MTX_NOPUSH | G_MTX_LOAD | G_MTX_PROJECTION);
+    gSPMatrix(gfx++, &this->modelView, G_MTX_NOPUSH | G_MTX_LOAD | G_MTX_MODELVIEW);
+    gSPSegment(gfx++, 0xA, this->frame == 0 ? this->vtxFrame1 : this->vtxFrame2);
+    gSPSegment(gfx++, 0xB, this->zBuffer);
+    gSPDisplayList(gfx++, fbdemo_gfx_init);
+    gSPDisplayList(gfx++, this->gfx);
+    gDPPipeSync(gfx++);
+    this->frame ^= 1;
+    *gfxP = gfx;
+}
+
+
+extern void fbdemo_move(void){
+
+}
\ No newline at end of file
diff --git a/src/libultra/xprintf.c b/src/libultra/xprintf.c
index 74eafe05..9cdb043f 100644
--- a/src/libultra/xprintf.c
+++ b/src/libultra/xprintf.c
@@ -42,7 +42,7 @@ void _Putfld(_Pft*, va_list, u8, u8*);
 
 /* These functions seem to have 04,p enabled */
 #pragma optimize_for_size off
-s32 _Printf(void* (*pfn)(void*, const char*, int), void* arg, const char* fmt,
+int _Printf(void* (*pfn)(void*, const char*, int), void* arg, const char* fmt,
             va_list ap) {
   /* Unused static variables to match position of locals */
   static int unused0;