diff --git a/src/GPU2D.cpp b/src/GPU2D.cpp
index 72f74091..dc8d348f 100644
--- a/src/GPU2D.cpp
+++ b/src/GPU2D.cpp
@@ -73,6 +73,8 @@
 //
 // mosaic:
 // * mosaic grid starts at 0,0 regardless of the BG/sprite position
+// * when changing it midframe: new X setting is applied immediately, new Y setting is applied only
+//   after the end of the current mosaic row
 
 // TODO: find which parts of DISPCNT are latched. for example, not possible to change video mode midframe.
 
@@ -109,6 +111,10 @@ void GPU2D::Reset()
     BGMosaicSize[1] = 0;
     OBJMosaicSize[0] = 0;
     OBJMosaicSize[1] = 0;
+    BGMosaicY = 0;
+    BGMosaicYMax = 0;
+    OBJMosaicY = 0;
+    OBJMosaicYMax = 0;
 
     BlendCnt = 0;
     EVA = 16;
@@ -624,6 +630,11 @@ void GPU2D::VBlankEnd()
     BGXRefInternal[1] = BGXRef[1];
     BGYRefInternal[0] = BGYRef[0];
     BGYRefInternal[1] = BGYRef[1];
+
+    BGMosaicY = 0;
+    BGMosaicYMax = BGMosaicSize[1];
+    OBJMosaicY = 0;
+    OBJMosaicYMax = OBJMosaicSize[1];
 }
 
 
@@ -1179,6 +1190,22 @@ void GPU2D::DrawScanline_Mode1(u32 line, u32* dst)
             break;
         }
     }
+
+    if (BGMosaicY >= BGMosaicYMax)
+    {
+        BGMosaicY = 0;
+        BGMosaicYMax = BGMosaicSize[1];
+    }
+    else
+        BGMosaicY++;
+
+    if (OBJMosaicY >= OBJMosaicYMax)
+    {
+        OBJMosaicY = 0;
+        OBJMosaicYMax = OBJMosaicSize[1];
+    }
+    else
+        OBJMosaicY++;
 }
 
 
@@ -1230,6 +1257,7 @@ void GPU2D::DrawBG_Text(u32 line, u32* dst, u32 bgnum)
 {
     u8* windowmask = (u8*)&dst[256*2];
     u16 bgcnt = BGCnt[bgnum];
+    u32 xmos = 0, xmossize = 0;
 
     u32 tilesetaddr, tilemapaddr;
     u16* pal;
@@ -1238,6 +1266,13 @@ void GPU2D::DrawBG_Text(u32 line, u32* dst, u32 bgnum)
     u16 xoff = BGXPos[bgnum];
     u16 yoff = BGYPos[bgnum] + line;
 
+    if (bgcnt & 0x0040)
+    {
+        // mosaic
+        yoff -= BGMosaicY;
+        xmossize = BGMosaicSize[0];
+    }
+
     u32 widexmask = (bgcnt & 0x4000) ? 0x100 : 0;
 
     extpal = (DispCnt & 0x40000000);
@@ -1271,6 +1306,7 @@ void GPU2D::DrawBG_Text(u32 line, u32* dst, u32 bgnum)
     u16 curtile;
     u16* curpal;
     u32 pixelsaddr;
+    u8 color;
 
     if (bgcnt & 0x0080)
     {
@@ -1306,9 +1342,14 @@ void GPU2D::DrawBG_Text(u32 line, u32* dst, u32 bgnum)
             // draw pixel
             if (windowmask[i] & (1<<bgnum))
             {
-                u8 color;
-                u32 tilexoff = (curtile & 0x0400) ? (7-(xoff&0x7)) : (xoff&0x7);
-                color = GPU::ReadVRAM_BG<u8>(pixelsaddr + tilexoff);
+                if (xmos == 0)
+                {
+                    u32 tilexoff = (curtile & 0x0400) ? (7-(xoff&0x7)) : (xoff&0x7);
+                    color = GPU::ReadVRAM_BG<u8>(pixelsaddr + tilexoff);
+                    xmos = xmossize;
+                }
+                else
+                    xmos--;
 
                 if (color)
                     DrawPixel(&dst[i], curpal[color], 0x01000000<<bgnum);
@@ -1346,16 +1387,21 @@ void GPU2D::DrawBG_Text(u32 line, u32* dst, u32 bgnum)
             // TODO: optimize VRAM access
             if (windowmask[i] & (1<<bgnum))
             {
-                u8 color;
-                u32 tilexoff = (curtile & 0x0400) ? (7-(xoff&0x7)) : (xoff&0x7);
-                if (tilexoff & 0x1)
+                if (xmos == 0)
                 {
-                    color = GPU::ReadVRAM_BG<u8>(pixelsaddr + (tilexoff >> 1)) >> 4;
+                    u32 tilexoff = (curtile & 0x0400) ? (7-(xoff&0x7)) : (xoff&0x7);
+                    if (tilexoff & 0x1)
+                    {
+                        color = GPU::ReadVRAM_BG<u8>(pixelsaddr + (tilexoff >> 1)) >> 4;
+                    }
+                    else
+                    {
+                        color = GPU::ReadVRAM_BG<u8>(pixelsaddr + (tilexoff >> 1)) & 0x0F;
+                    }
+                    xmos = xmossize;
                 }
                 else
-                {
-                    color = GPU::ReadVRAM_BG<u8>(pixelsaddr + (tilexoff >> 1)) & 0x0F;
-                }
+                    xmos--;
 
                 if (color)
                     DrawPixel(&dst[i], curpal[color], 0x01000000<<bgnum);
@@ -1370,6 +1416,7 @@ void GPU2D::DrawBG_Affine(u32 line, u32* dst, u32 bgnum)
 {
     u8* windowmask = (u8*)&dst[256*2];
     u16 bgcnt = BGCnt[bgnum];
+    u32 xmos = 0, xmossize = 0;
 
     u32 tilesetaddr, tilemapaddr;
     u16* pal;
@@ -1396,6 +1443,14 @@ void GPU2D::DrawBG_Affine(u32 line, u32* dst, u32 bgnum)
     s32 rotX = BGXRefInternal[bgnum-2];
     s32 rotY = BGYRefInternal[bgnum-2];
 
+    if (bgcnt & 0x0040)
+    {
+        // mosaic
+        rotX -= (BGMosaicY * rotB);
+        rotY -= (BGMosaicY * rotD);
+        xmossize = BGMosaicSize[0];
+    }
+
     if (Num)
     {
         tilesetaddr = 0x06200000 + ((bgcnt & 0x003C) << 12);
@@ -1412,24 +1467,37 @@ void GPU2D::DrawBG_Affine(u32 line, u32* dst, u32 bgnum)
     }
 
     u16 curtile;
+    u8 color;
 
     yshift -= 3;
 
     for (int i = 0; i < 256; i++)
     {
-        if ((!((rotX|rotY) & overflowmask)) && (windowmask[i] & (1<<bgnum)))
+        if (windowmask[i] & (1<<bgnum))
         {
-            curtile = GPU::ReadVRAM_BG<u8>(tilemapaddr + ((((rotY & coordmask) >> 11) << yshift) + ((rotX & coordmask) >> 11)));
+            if (xmos > 0)
+            {
+                if (color)
+                    DrawPixel(&dst[i], pal[color], 0x01000000<<bgnum);
 
-            // draw pixel
-            u8 color;
-            u32 tilexoff = (rotX >> 8) & 0x7;
-            u32 tileyoff = (rotY >> 8) & 0x7;
+                xmos--;
+            }
+            else
+            if ((!((rotX|rotY) & overflowmask)))
+            {
+                curtile = GPU::ReadVRAM_BG<u8>(tilemapaddr + ((((rotY & coordmask) >> 11) << yshift) + ((rotX & coordmask) >> 11)));
 
-            color = GPU::ReadVRAM_BG<u8>(tilesetaddr + (curtile << 6) + (tileyoff << 3) + tilexoff);
+                // draw pixel
+                u32 tilexoff = (rotX >> 8) & 0x7;
+                u32 tileyoff = (rotY >> 8) & 0x7;
 
-            if (color)
-                DrawPixel(&dst[i], pal[color], 0x01000000<<bgnum);
+                color = GPU::ReadVRAM_BG<u8>(tilesetaddr + (curtile << 6) + (tileyoff << 3) + tilexoff);
+
+                if (color)
+                    DrawPixel(&dst[i], pal[color], 0x01000000<<bgnum);
+
+                xmos = xmossize;
+            }
         }
 
         rotX += rotA;
@@ -1444,6 +1512,7 @@ void GPU2D::DrawBG_Extended(u32 line, u32* dst, u32 bgnum)
 {
     u8* windowmask = (u8*)&dst[256*2];
     u16 bgcnt = BGCnt[bgnum];
+    u32 xmos = 0, xmossize = 0;
 
     u32 tilesetaddr, tilemapaddr;
     u16* pal;
@@ -1459,6 +1528,14 @@ void GPU2D::DrawBG_Extended(u32 line, u32* dst, u32 bgnum)
     s32 rotX = BGXRefInternal[bgnum-2];
     s32 rotY = BGYRefInternal[bgnum-2];
 
+    if (bgcnt & 0x0040)
+    {
+        // mosaic
+        rotX -= (BGMosaicY * rotB);
+        rotY -= (BGMosaicY * rotD);
+        xmossize = BGMosaicSize[0];
+    }
+
     if (bgcnt & 0x0080)
     {
         // bitmap modes
@@ -1492,14 +1569,29 @@ void GPU2D::DrawBG_Extended(u32 line, u32* dst, u32 bgnum)
         {
             // direct color bitmap
 
+            u16 color;
+
             for (int i = 0; i < 256; i++)
             {
-                if (!(rotX & ofxmask) && !(rotY & ofymask) && (windowmask[i] & (1<<bgnum)))
+                if (windowmask[i] & (1<<bgnum))
                 {
-                    u16 color = GPU::ReadVRAM_BG<u16>(tilemapaddr + (((((rotY & ymask) >> 8) << yshift) + ((rotX & xmask) >> 8)) << 1));
+                    if (xmos > 0)
+                    {
+                        if (color & 0x8000)
+                            DrawPixel(&dst[i], color, 0x01000000<<bgnum);
 
-                    if (color & 0x8000)
-                        DrawPixel(&dst[i], color, 0x01000000<<bgnum);
+                        xmos--;
+                    }
+                    else
+                    if (!(rotX & ofxmask) && !(rotY & ofymask))
+                    {
+                        color = GPU::ReadVRAM_BG<u16>(tilemapaddr + (((((rotY & ymask) >> 8) << yshift) + ((rotX & xmask) >> 8)) << 1));
+
+                        if (color & 0x8000)
+                            DrawPixel(&dst[i], color, 0x01000000<<bgnum);
+
+                        xmos = xmossize;
+                    }
                 }
 
                 rotX += rotA;
@@ -1513,14 +1605,29 @@ void GPU2D::DrawBG_Extended(u32 line, u32* dst, u32 bgnum)
             if (Num) pal = (u16*)&GPU::Palette[0x400];
             else     pal = (u16*)&GPU::Palette[0];
 
+            u8 color;
+
             for (int i = 0; i < 256; i++)
             {
-                if (!(rotX & ofxmask) && !(rotY & ofymask) && (windowmask[i] & (1<<bgnum)))
+                if (windowmask[i] & (1<<bgnum))
                 {
-                    u8 color = GPU::ReadVRAM_BG<u8>(tilemapaddr + (((rotY & ymask) >> 8) << yshift) + ((rotX & xmask) >> 8));
+                    if (xmos > 0)
+                    {
+                        if (color)
+                            DrawPixel(&dst[i], pal[color], 0x01000000<<bgnum);
 
-                    if (color)
-                        DrawPixel(&dst[i], pal[color], 0x01000000<<bgnum);
+                        xmos--;
+                    }
+                    else
+                    if (!(rotX & ofxmask) && !(rotY & ofymask))
+                    {
+                        color = GPU::ReadVRAM_BG<u8>(tilemapaddr + (((rotY & ymask) >> 8) << yshift) + ((rotX & xmask) >> 8));
+
+                        if (color)
+                            DrawPixel(&dst[i], pal[color], 0x01000000<<bgnum);
+
+                        xmos = xmossize;
+                    }
                 }
 
                 rotX += rotA;
@@ -1563,30 +1670,43 @@ void GPU2D::DrawBG_Extended(u32 line, u32* dst, u32 bgnum)
 
         u16 curtile;
         u16* curpal;
+        u8 color;
 
         yshift -= 3;
 
         for (int i = 0; i < 256; i++)
         {
-            if ((!((rotX|rotY) & overflowmask)) && (windowmask[i] & (1<<bgnum)))
+            if (windowmask[i] & (1<<bgnum))
             {
-                curtile = GPU::ReadVRAM_BG<u16>(tilemapaddr + (((((rotY & coordmask) >> 11) << yshift) + ((rotX & coordmask) >> 11)) << 1));
+                if (xmos > 0)
+                {
+                    if (color)
+                        DrawPixel(&dst[i], curpal[color], 0x01000000<<bgnum);
 
-                if (extpal) curpal = GetBGExtPal(bgnum, curtile>>12);
-                else        curpal = pal;
+                    xmos--;
+                }
+                else
+                if ((!((rotX|rotY) & overflowmask)))
+                {
+                    curtile = GPU::ReadVRAM_BG<u16>(tilemapaddr + (((((rotY & coordmask) >> 11) << yshift) + ((rotX & coordmask) >> 11)) << 1));
 
-                // draw pixel
-                u8 color;
-                u32 tilexoff = (rotX >> 8) & 0x7;
-                u32 tileyoff = (rotY >> 8) & 0x7;
+                    if (extpal) curpal = GetBGExtPal(bgnum, curtile>>12);
+                    else        curpal = pal;
 
-                if (curtile & 0x0400) tilexoff = 7-tilexoff;
-                if (curtile & 0x0800) tileyoff = 7-tileyoff;
+                    // draw pixel
+                    u32 tilexoff = (rotX >> 8) & 0x7;
+                    u32 tileyoff = (rotY >> 8) & 0x7;
 
-                color = GPU::ReadVRAM_BG<u8>(tilesetaddr + ((curtile & 0x03FF) << 6) + (tileyoff << 3) + tilexoff);
+                    if (curtile & 0x0400) tilexoff = 7-tilexoff;
+                    if (curtile & 0x0800) tileyoff = 7-tileyoff;
 
-                if (color)
-                    DrawPixel(&dst[i], curpal[color], 0x01000000<<bgnum);
+                    color = GPU::ReadVRAM_BG<u8>(tilesetaddr + ((curtile & 0x03FF) << 6) + (tileyoff << 3) + tilexoff);
+
+                    if (color)
+                        DrawPixel(&dst[i], curpal[color], 0x01000000<<bgnum);
+
+                    xmos = xmossize;
+                }
             }
 
             rotX += rotA;
@@ -1602,6 +1722,7 @@ void GPU2D::DrawBG_Large(u32 line, u32* dst) // BG is always BG2
 {
     u8* windowmask = (u8*)&dst[256*2];
     u16 bgcnt = BGCnt[2];
+    u32 xmos = 0, xmossize = 0;
 
     u32 tilesetaddr, tilemapaddr;
     u16* pal;
@@ -1636,6 +1757,14 @@ void GPU2D::DrawBG_Large(u32 line, u32* dst) // BG is always BG2
     s32 rotX = BGXRefInternal[0];
     s32 rotY = BGYRefInternal[0];
 
+    if (bgcnt & 0x0040)
+    {
+        // mosaic
+        rotX -= (BGMosaicY * rotB);
+        rotY -= (BGMosaicY * rotD);
+        xmossize = BGMosaicSize[0];
+    }
+
     if (Num) tilemapaddr = 0x06200000;
     else     tilemapaddr = 0x06000000;
 
@@ -1644,14 +1773,27 @@ void GPU2D::DrawBG_Large(u32 line, u32* dst) // BG is always BG2
     if (Num) pal = (u16*)&GPU::Palette[0x400];
     else     pal = (u16*)&GPU::Palette[0];
 
+    u8 color;
+
     for (int i = 0; i < 256; i++)
     {
-        if (!(rotX & ofxmask) && !(rotY & ofymask) && (windowmask[i] & (1<<2)))
+        if (windowmask[i] & (1<<2))
         {
-            u8 color = GPU::ReadVRAM_BG<u8>(tilemapaddr + (((rotY & ymask) >> 8) << yshift) + ((rotX & xmask) >> 8));
+            if (xmos > 0)
+            {
+                if (color)
+                    DrawPixel(&dst[i], pal[color], 0x01000000<<2);
 
-            if (color)
-                DrawPixel(&dst[i], pal[color], 0x01000000<<2);
+                xmos--;
+            }
+            else
+            if (!(rotX & ofxmask) && !(rotY & ofymask))
+            {
+                color = GPU::ReadVRAM_BG<u8>(tilemapaddr + (((rotY & ymask) >> 8) << yshift) + ((rotX & xmask) >> 8));
+
+                if (color)
+                    DrawPixel(&dst[i], pal[color], 0x01000000<<2);
+            }
         }
 
         rotX += rotA;
@@ -1843,17 +1985,29 @@ void GPU2D::DrawSpritesWindow(u32 line, u8* dst)
 }
 
 template<bool window>
-void GPU2D::DrawSprite_Rotscale(u16* attrib, u16* rotparams, u32 boundwidth, u32 boundheight, u32 width, u32 height, s32 xpos, u32 ypos, u32* dst)
+void GPU2D::DrawSprite_Rotscale(u16* attrib, u16* rotparams, u32 boundwidth, u32 boundheight, u32 width, u32 height, s32 xpos, s32 ypos, u32* dst)
 {
     u32 prio = ((attrib[2] & 0x0C00) << 6) | 0x8000;
     u32 tilenum = attrib[2] & 0x03FF;
     u32 spritemode = window ? 0 : ((attrib[0] >> 10) & 0x3);
+    u32 xmos = 0, xmossize = 0;
 
     u32 ytilefactor;
 
     s32 centerX = boundwidth >> 1;
     s32 centerY = boundheight >> 1;
 
+    if (attrib[0] & 0x1000)
+    {
+        // mosaic
+        ypos -= OBJMosaicY;
+        if (ypos < 0) ypos = 0;
+        xmossize = OBJMosaicSize[0];
+
+        if (xpos > 0)
+            xmos = (xmossize+1) - (xpos % (xmossize+1));
+    }
+
     u32 xoff;
     if (xpos >= 0)
     {
@@ -1878,6 +2032,8 @@ void GPU2D::DrawSprite_Rotscale(u16* attrib, u16* rotparams, u32 boundwidth, u32
     width <<= 8;
     height <<= 8;
 
+    u16 color = 0; // transparent in all cases
+
     if (spritemode == 3)
     {
         u32 alpha = attrib[2] >> 12;
@@ -1914,12 +2070,20 @@ void GPU2D::DrawSprite_Rotscale(u16* attrib, u16* rotparams, u32 boundwidth, u32
         }
 
         u32 pixelsaddr = (Num ? 0x06600000 : 0x06400000) + tilenum;
+        if (xmos && !(attrib[0]&0x0200))
+            color = GPU::ReadVRAM_OBJ<u16>(pixelsaddr + ((rotY >> 8) * ytilefactor) + ((rotX >> 8) << 1));
 
         for (; xoff < boundwidth;)
         {
             if ((u32)rotX < width && (u32)rotY < height)
             {
-                u16 color = GPU::ReadVRAM_OBJ<u16>(pixelsaddr + ((rotY >> 8) * ytilefactor) + ((rotX >> 8) << 1));
+                if (xmos == 0)
+                {
+                    color = GPU::ReadVRAM_OBJ<u16>(pixelsaddr + ((rotY >> 8) * ytilefactor) + ((rotX >> 8) << 1));
+                    xmos = xmossize;
+                }
+                else
+                    xmos--;
 
                 if (color & 0x8000)
                 {
@@ -1927,6 +2091,11 @@ void GPU2D::DrawSprite_Rotscale(u16* attrib, u16* rotparams, u32 boundwidth, u32
                     else        dst[xpos] = color | prio;
                 }
             }
+            else
+            {
+                if (xmos == 0) xmos = xmossize;
+                else           xmos--;
+            }
 
             rotX += rotA;
             rotY += rotC;
@@ -1965,11 +2134,20 @@ void GPU2D::DrawSprite_Rotscale(u16* attrib, u16* rotparams, u32 boundwidth, u32
                 else        pal = (u16*)&GPU::Palette[Num ? 0x600 : 0x200];
             }
 
+            if (xmos && !(attrib[0]&0x0200))
+                color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr + ((rotY>>11)*ytilefactor) + ((rotY&0x700)>>5) + ((rotX>>11)*64) + ((rotX&0x700)>>8));
+
             for (; xoff < boundwidth;)
             {
                 if ((u32)rotX < width && (u32)rotY < height)
                 {
-                    u8 color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr + ((rotY>>11)*ytilefactor) + ((rotY&0x700)>>5) + ((rotX>>11)*64) + ((rotX&0x700)>>8));
+                    if (xmos == 0)
+                    {
+                        color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr + ((rotY>>11)*ytilefactor) + ((rotY&0x700)>>5) + ((rotX>>11)*64) + ((rotX&0x700)>>8));
+                        xmos = xmossize;
+                    }
+                    else
+                        xmos--;
 
                     if (color)
                     {
@@ -1977,6 +2155,11 @@ void GPU2D::DrawSprite_Rotscale(u16* attrib, u16* rotparams, u32 boundwidth, u32
                         else        dst[xpos] = pal[color] | prio;
                     }
                 }
+                else
+                {
+                    if (xmos == 0) xmos = xmossize;
+                    else           xmos--;
+                }
 
                 rotX += rotA;
                 rotY += rotC;
@@ -1998,16 +2181,31 @@ void GPU2D::DrawSprite_Rotscale(u16* attrib, u16* rotparams, u32 boundwidth, u32
                 pal += (attrib[2] & 0xF000) >> 8;
             }
 
+            if (xmos && !(attrib[0]&0x0200))
+            {
+                color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr + ((rotY>>11)*ytilefactor) + ((rotY&0x700)>>6) + ((rotX>>11)*32) + ((rotX&0x700)>>9));
+                if (rotX & 0x100)
+                    color >>= 4;
+                else
+                    color &= 0x0F;
+            }
+
             for (; xoff < boundwidth;)
             {
                 if ((u32)rotX < width && (u32)rotY < height)
                 {
-                    u8 color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr + ((rotY>>11)*ytilefactor) + ((rotY&0x700)>>6) + ((rotX>>11)*32) + ((rotX&0x700)>>9));
+                    if (xmos == 0)
+                    {
+                        color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr + ((rotY>>11)*ytilefactor) + ((rotY&0x700)>>6) + ((rotX>>11)*32) + ((rotX&0x700)>>9));
+                        if (rotX & 0x100)
+                            color >>= 4;
+                        else
+                            color &= 0x0F;
 
-                    if (rotX & 0x100)
-                        color >>= 4;
+                        xmos = xmossize;
+                    }
                     else
-                        color &= 0x0F;
+                        xmos--;
 
                     if (color)
                     {
@@ -2015,6 +2213,11 @@ void GPU2D::DrawSprite_Rotscale(u16* attrib, u16* rotparams, u32 boundwidth, u32
                         else        dst[xpos] = pal[color] | prio;
                     }
                 }
+                else
+                {
+                    if (xmos == 0) xmos = xmossize;
+                    else           xmos--;
+                }
 
                 rotX += rotA;
                 rotY += rotC;
@@ -2026,14 +2229,26 @@ void GPU2D::DrawSprite_Rotscale(u16* attrib, u16* rotparams, u32 boundwidth, u32
 }
 
 template<bool window>
-void GPU2D::DrawSprite_Normal(u16* attrib, u32 width, s32 xpos, u32 ypos, u32* dst)
+void GPU2D::DrawSprite_Normal(u16* attrib, u32 width, s32 xpos, s32 ypos, u32* dst)
 {
     u32 prio = ((attrib[2] & 0x0C00) << 6) | 0x8000;
     u32 tilenum = attrib[2] & 0x03FF;
     u32 spritemode = window ? 0 : ((attrib[0] >> 10) & 0x3);
+    u32 xmos = 0, xmossize = 0;
 
     u32 wmask = width - 8; // really ((width - 1) & ~0x7)
 
+    if (attrib[0] & 0x1000)
+    {
+        // mosaic
+        ypos -= OBJMosaicY;
+        if (ypos < 0) ypos = 0;
+        xmossize = OBJMosaicSize[0];
+
+        if (xpos > 0)
+            xmos = (xmossize+1) - (xpos % (xmossize+1));
+    }
+
     u32 xoff;
     u32 xend = width;
     if (xpos >= 0)
@@ -2048,6 +2263,8 @@ void GPU2D::DrawSprite_Normal(u16* attrib, u32 width, s32 xpos, u32 ypos, u32* d
         xpos = 0;
     }
 
+    u16 color = 0; // transparent in all cases
+
     if (spritemode == 3)
     {
         // bitmap sprite
@@ -2090,10 +2307,18 @@ void GPU2D::DrawSprite_Normal(u16* attrib, u32 width, s32 xpos, u32 ypos, u32* d
         if (attrib[1] & 0x1000)
         {
             pixelsaddr += ((width-1 - xoff) << 1);
+            if (xmos) color = GPU::ReadVRAM_OBJ<u16>(pixelsaddr);
 
             for (; xoff < xend;)
             {
-                u16 color = GPU::ReadVRAM_OBJ<u16>(pixelsaddr);
+                if (xmos == 0)
+                {
+                    color = GPU::ReadVRAM_OBJ<u16>(pixelsaddr);
+                    xmos = xmossize;
+                }
+                else
+                    xmos--;
+
                 pixelsaddr -= 2;
 
                 if (color & 0x8000)
@@ -2109,10 +2334,18 @@ void GPU2D::DrawSprite_Normal(u16* attrib, u32 width, s32 xpos, u32 ypos, u32* d
         else
         {
             pixelsaddr += (xoff << 1);
+            if (xmos) color = GPU::ReadVRAM_OBJ<u16>(pixelsaddr);
 
             for (; xoff < xend;)
             {
-                u16 color = GPU::ReadVRAM_OBJ<u16>(pixelsaddr);
+                if (xmos == 0)
+                {
+                    color = GPU::ReadVRAM_OBJ<u16>(pixelsaddr);
+                    xmos = xmossize;
+                }
+                else
+                    xmos--;
+
                 pixelsaddr += 2;
 
                 if (color & 0x8000)
@@ -2161,10 +2394,18 @@ void GPU2D::DrawSprite_Normal(u16* attrib, u32 width, s32 xpos, u32 ypos, u32* d
             {
                 pixelsaddr += (((width-1 - xoff) & wmask) << 3);
                 pixelsaddr += ((width-1 - xoff) & 0x7);
+                if (xmos) color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr);
 
                 for (; xoff < xend;)
                 {
-                    u8 color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr);
+                    if (xmos == 0)
+                    {
+                        color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr);
+                        xmos = xmossize;
+                    }
+                    else
+                        xmos--;
+
                     pixelsaddr--;
 
                     if (color)
@@ -2182,10 +2423,18 @@ void GPU2D::DrawSprite_Normal(u16* attrib, u32 width, s32 xpos, u32 ypos, u32* d
             {
                 pixelsaddr += ((xoff & wmask) << 3);
                 pixelsaddr += (xoff & 0x7);
+                if (xmos) color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr);
 
                 for (; xoff < xend;)
                 {
-                    u8 color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr);
+                    if (xmos == 0)
+                    {
+                        color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr);
+                        xmos = xmossize;
+                    }
+                    else
+                        xmos--;
+
                     pixelsaddr++;
 
                     if (color)
@@ -2218,19 +2467,24 @@ void GPU2D::DrawSprite_Normal(u16* attrib, u32 width, s32 xpos, u32 ypos, u32* d
             {
                 pixelsaddr += (((width-1 - xoff) & wmask) << 2);
                 pixelsaddr += (((width-1 - xoff) & 0x7) >> 1);
+                if (xmos)
+                {
+                    if (xoff & 0x1) color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr) & 0x0F;
+                    else            color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr) >> 4;
+                }
 
                 for (; xoff < xend;)
                 {
-                    u8 color;
-                    if (xoff & 0x1)
+                    if (xmos == 0)
                     {
-                        color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr) & 0x0F;
-                        pixelsaddr--;
+                        if (xoff & 0x1) color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr) & 0x0F;
+                        else            color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr) >> 4;
+                        xmos = xmossize;
                     }
                     else
-                    {
-                        color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr) >> 4;
-                    }
+                        xmos--;
+
+                    if (xoff & 0x1) pixelsaddr--;
 
                     if (color)
                     {
@@ -2247,19 +2501,24 @@ void GPU2D::DrawSprite_Normal(u16* attrib, u32 width, s32 xpos, u32 ypos, u32* d
             {
                 pixelsaddr += ((xoff & wmask) << 2);
                 pixelsaddr += ((xoff & 0x7) >> 1);
+                if (xmos)
+                {
+                    if (xoff & 0x1) color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr) >> 4;
+                    else            color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr) & 0x0F;
+                }
 
                 for (; xoff < xend;)
                 {
-                    u8 color;
-                    if (xoff & 0x1)
+                    if (xmos == 0)
                     {
-                        color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr) >> 4;
-                        pixelsaddr++;
+                        if (xoff & 0x1) color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr) >> 4;
+                        else            color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr) & 0x0F;
+                        xmos = xmossize;
                     }
                     else
-                    {
-                        color = GPU::ReadVRAM_OBJ<u8>(pixelsaddr) & 0x0F;
-                    }
+                        xmos--;
+
+                    pixelsaddr++;
 
                     if (color)
                     {
diff --git a/src/GPU2D.h b/src/GPU2D.h
index 3e9dc36b..d059fa06 100644
--- a/src/GPU2D.h
+++ b/src/GPU2D.h
@@ -93,6 +93,8 @@ private:
 
     u8 BGMosaicSize[2];
     u8 OBJMosaicSize[2];
+    u8 BGMosaicY, BGMosaicYMax;
+    u8 OBJMosaicY, OBJMosaicYMax;
 
     u16 BlendCnt;
     u16 BlendAlpha;
@@ -123,8 +125,8 @@ private:
     void InterleaveSprites(u32* buf, u32 prio, u32* dst);
     void DrawSprites(u32 line, u32* dst);
     void DrawSpritesWindow(u32 line, u8* dst);
-    template<bool window> void DrawSprite_Rotscale(u16* attrib, u16* rotparams, u32 boundwidth, u32 boundheight, u32 width, u32 height, s32 xpos, u32 ypos, u32* dst);
-    template<bool window> void DrawSprite_Normal(u16* attrib, u32 width, s32 xpos, u32 ypos, u32* dst);
+    template<bool window> void DrawSprite_Rotscale(u16* attrib, u16* rotparams, u32 boundwidth, u32 boundheight, u32 width, u32 height, s32 xpos, s32 ypos, u32* dst);
+    template<bool window> void DrawSprite_Normal(u16* attrib, u32 width, s32 xpos, s32 ypos, u32* dst);
 
     void DoCapture(u32 line, u32 width, u32* src);