diff --git a/src/burn/drv/pre90s/d_megasys1.cpp b/src/burn/drv/pre90s/d_megasys1.cpp
index d30b04c86..7d42ff922 100644
--- a/src/burn/drv/pre90s/d_megasys1.cpp
+++ b/src/burn/drv/pre90s/d_megasys1.cpp
@@ -2899,7 +2899,8 @@ static inline void draw_16x16_priority_sprite(INT32 code, INT32 color, INT32 sx,
 
 	UINT8 *gfx = DrvGfxROM[3] + (code * 0x100);
 
-	INT32 flip = (flipy ? 0xf0 : 0) | (flipx ? 0x0f : 0);
+	flipy = (flipy) ? 0x0f : 0;
+	flipx = (flipx) ? 0x0f : 0;
 
 	color = (color * 16) + layer_color_config[3];
 
@@ -2912,9 +2913,8 @@ static inline void draw_16x16_priority_sprite(INT32 code, INT32 color, INT32 sx,
 		{
 			if (sx < 0 || sy < 0 || sx >= nScreenWidth || sy >= nScreenHeight) continue;	
 
-			INT32 pxl = gfx[((y*16)+x)^flip];
-			if (mosaic) // ignore the warnings :) -dink
-				pxl = gfx[((y*16+y^mosaic*16)+(mosaic&x)+(x^mosaic&mosaic))^flip];
+			INT32 pxl = gfx[(((y ^ flipy) & ~mosaic)*16) + ((x ^ flipx) & ~mosaic)];
+
 			if (pxl != 0x0f) {
 				if ((priority & (1 << (prio[x] & 0x1f))) == 0 && prio[x] < 0x80) {
 					dest[x] = pxl + color;
@@ -2957,6 +2957,7 @@ static void System1A_draw_sprites()
 			INT32 flipy = attr & 0x80;
 			INT32 pri  = (attr & 0x08) ? 0x0c : 0x0a;
 			INT32 mosaic = (attr & 0x0f00)>>8;
+			//INT32 mossol = (attr & 0x1000)>>8; //not yet
 			code = (code & 0xfff) + ((sprite_bank & 1) << 12);
 			if (DrvTransTab[3][code]) continue;