diff --git a/src/mame/includes/stv.h b/src/mame/includes/stv.h
index f26121288a1..60412099cea 100644
--- a/src/mame/includes/stv.h
+++ b/src/mame/includes/stv.h
@@ -57,6 +57,7 @@ public:
 	    UINT8     *gfx_decode;
 		UINT16    lopr;
 		UINT16    copr;
+		UINT16    ewdr;
 
 		int       local_x;
 		int       local_y;
diff --git a/src/mame/machine/stvcd.c b/src/mame/machine/stvcd.c
index 189e0d370a2..97dffcd0ab0 100644
--- a/src/mame/machine/stvcd.c
+++ b/src/mame/machine/stvcd.c
@@ -321,7 +321,9 @@ static void cd_free_block(blockT *blktofree)
 	CDROM_LOG(("cd_free_block: %x\n", (UINT32)(FPTR)blktofree))
 
 	if(blktofree == NULL)
+	{
 		return;
+	}
 
 	for (i = 0; i < 200; i++)
 	{
@@ -685,14 +687,18 @@ static void cd_writeWord(running_machine &machine, UINT32 addr, UINT16 data)
 				// CR1 & 4 = don't confirm mode 2 subheader
 				// CR1 & 8 = retry reading mode 2 sectors
 				// CR1 & 10 = force single-speed
+				// CR1 & 80 = no change flag (done by Assault Suit Leynos 2)
 			CDROM_LOG(("%s:CD: Initialize CD system\n", machine.describe_context()))
-			hirqreg &= 0xffe5;
+			if((cr1 & 0x80) == 0x00)
+			{
+				cd_stat = CD_STAT_PAUSE;
+				cd_curfad = 150;
+				fadstoplay = 0;
+				in_buffer = 0;
+				buffull = 0;
+				hirqreg &= 0xffe5;
+			}
 			hirqreg |= (CMOK|ESEL);
-			cd_stat = CD_STAT_PAUSE;
-			cd_curfad = 150;
-			fadstoplay = 0;
-			in_buffer = 0;
-			buffull = 0;
 			cr_standard_return(cd_stat);
 			break;
 
@@ -1049,12 +1055,14 @@ static void cd_writeWord(running_machine &machine, UINT32 addr, UINT16 data)
 			break;
 
 		case 0x4800:	// Reset Selector
+			{
+			int i,j;
+
 			CDROM_LOG(("%s:CD: Reset Selector\n",   machine.describe_context()))
 
 			if((cr1 & 0xff) == 0x00)
 			{
 				UINT8 bufnum = cr3>>8;
-				int i;
 
 				if(bufnum < MAX_FILTERS)
 				{
@@ -1078,9 +1086,59 @@ static void cd_writeWord(running_machine &machine, UINT32 addr, UINT16 data)
 				return;
 			}
 
-			// ...
+			/* reset false filter output conditions */
+			if(cr1 & 0x80)
+			{
+				for(i=0;i<MAX_FILTERS;i++)
+					filters[i].condfalse = 0xff;
+			}
+
+			/* reset true filter output conditions */
+			if(cr1 & 0x40)
+			{
+				for(i=0;i<MAX_FILTERS;i++)
+					filters[i].condtrue = i;
+			}
+
+			/* reset filter conditions*/
+			if(cr1 & 0x10)
+			{
+				for(i=0;i<MAX_FILTERS;i++)
+				{
+					filters[i].fad = 0;
+					filters[i].range = 0xffffffff;
+					filters[i].mode = 0;
+					filters[i].chan = 0;
+					filters[i].smmask = 0;
+					filters[i].cimask = 0;
+					filters[i].fid = 0;
+					filters[i].smval = 0;
+					filters[i].cival = 0;
+				}
+			}
+
+			/* reset partition buffer data */
+			if(cr1 & 0x4)
+			{
+				for(i=0;i<MAX_FILTERS;i++)
+				{
+					for (j = 0; j < MAX_BLOCKS; j++)
+					{
+						cd_free_block(partitions[i].blocks[j]);
+						partitions[i].blocks[j] = (blockT *)NULL;
+						partitions[i].bnum[j] = 0xff;
+					}
+
+					partitions[i].size = -1;
+					partitions[i].numblks = 0;
+				}
+
+				buffull = sectorstore = 0;
+			}
+
 			hirqreg |= (CMOK|ESEL);
 			cr_standard_return(cd_stat);
+			}
 			break;
 
 		case 0x5000:	// get Buffer Size
diff --git a/src/mame/video/stvvdp1.c b/src/mame/video/stvvdp1.c
index 19b1d00e5ba..2a282cb0e2e 100644
--- a/src/mame/video/stvvdp1.c
+++ b/src/mame/video/stvvdp1.c
@@ -204,7 +204,7 @@ static void stv_clear_framebuffer( running_machine &machine, int which_framebuff
 	saturn_state *state = machine.driver_data<saturn_state>();
 
 	if ( VDP1_LOG ) logerror( "Clearing %d framebuffer\n", state->m_vdp1.framebuffer_current_draw );
-	memset( state->m_vdp1.framebuffer[ which_framebuffer ], 0, 1024 * 256 * sizeof(UINT16) * 2 );
+	memset( state->m_vdp1.framebuffer[ which_framebuffer ], state->m_vdp1.ewdr, 1024 * 256 * sizeof(UINT16) * 2 );
 }
 
 
@@ -226,7 +226,6 @@ static void stv_prepare_framebuffers( running_machine &machine )
 			state->m_vdp1.framebuffer_draw_lines[i] = &state->m_vdp1.framebuffer[0][0];
 			state->m_vdp1.framebuffer_display_lines[i] = &state->m_vdp1.framebuffer[1][0];
 		}
-
 	}
 	else
 	{
@@ -313,9 +312,7 @@ WRITE16_HANDLER( saturn_vdp1_regs_w )
 		case 0x06/2:
 			if ( VDP1_LOG ) logerror( "VDP1: Erase data set %08X\n", data );
 
-			if(data && data != 0x8000)
-				popmessage("EWDR set %08x, contact MAMEdev",STV_VDP1_EWDR);
-
+			state->m_vdp1.ewdr = STV_VDP1_EWDR;
 			break;
 		case 0x08/2:
 			if ( VDP1_LOG ) logerror( "VDP1: Erase upper-left coord set: %08X\n", data );
diff --git a/src/mame/video/stvvdp2.c b/src/mame/video/stvvdp2.c
index 106bad9ec6c..53a61d3097c 100644
--- a/src/mame/video/stvvdp2.c
+++ b/src/mame/video/stvvdp2.c
@@ -3028,7 +3028,7 @@ static void stv_vdp2_draw_basic_bitmap(running_machine &machine, bitmap_t *bitma
 	gfxdatalow = gfxdata + stv2_current_tilemap.bitmap_map * 0x20000;
 	gfxdata+=(
 	(stv2_current_tilemap.scrollx & (xlinesize-1)) +
-	((stv2_current_tilemap.scrolly) * (xlinesize)) + /* TODO: mask ysize, check me! */
+	((stv2_current_tilemap.scrolly & (ysize-1)) * (xlinesize)) + /* TODO: mask ysize, check me! */
 	(stv2_current_tilemap.bitmap_map * 0x20000)
 	);
 	gfxdatahigh = gfxdatalow + xlinesize*ysize;
@@ -4172,7 +4172,7 @@ static void stv_vdp2_check_tilemap(running_machine &machine, bitmap_t *bitmap, c
 		return;
 	}
 
-//	window_applied = 
+//	window_applied =
 	stv_vdp2_apply_window_on_layer(machine,&mycliprect);
 
 	if (stv2_current_tilemap.bitmap_enable) // this layer is a bitmap