diff --git a/src/device/keyboard_xt.c b/src/device/keyboard_xt.c
index 9a234b6eb..7af93103d 100644
--- a/src/device/keyboard_xt.c
+++ b/src/device/keyboard_xt.c
@@ -330,7 +330,8 @@ const scancode scancode_xt[512] = {
 static uint8_t	key_queue[16];
 static int	key_queue_start = 0,
 		key_queue_end = 0;
-static int	is_t1x00 = 0;
+static int	is_tandy = 0, is_t1x00 = 0,
+		is_amstrad = 0;
 
 
 #ifdef ENABLE_KEYBOARD_XT_LOG
@@ -425,9 +426,17 @@ kbd_adddata_process(uint16_t val, void (*adddata)(uint16_t val))
     if (!adddata)
 	return;
 
+    if (is_tandy) {
+	adddata(val);
+	return;
+    }
+
     keyboard_get_states(NULL, &num_lock, NULL);
     shift_states = keyboard_get_shift() & STATE_SHIFT_MASK;
 
+    if (is_amstrad)
+	num_lock = !num_lock;
+
     switch(val) {
 	case FAKE_LSHIFT_ON:
 		if (num_lock) {
@@ -553,15 +562,13 @@ kbd_read(uint16_t port, void *priv)
 				ret = ((mem_size-64) / 32) & 0x0f;
 			else
 				ret = ((mem_size-64) / 32) >> 4;
-		} 
-        else if (kbd->type == 8) {
-            /* Olivetti M19 */
-            if (kbd->pb & 0x04)
+		}  else if (kbd->type == 8) {
+			/* Olivetti M19 */
+			if (kbd->pb & 0x04)
 				ret = kbd->pd;
-            else 
-                ret = kbd->pd >> 4;
-        } 
-        else {
+			else 
+				ret = kbd->pd >> 4;
+		} else {
 			if (kbd->pb & 0x08)
 				ret = kbd->pd >> 4;
 			else {
@@ -613,6 +620,13 @@ kbd_reset(void *priv)
 }
 
 
+void
+keyboard_set_is_amstrad(int ams)
+{
+    is_amstrad = ams;
+}
+
+
 static void *
 kbd_init(const device_t *info)
 {
@@ -727,8 +741,11 @@ kbd_init(const device_t *info)
 
     keyboard_set_table(scancode_xt);
 
+    is_tandy = (kbd->type == 5);
     is_t1x00 = (kbd->type == 6);
 
+    is_amstrad = 0;
+
     return(kbd);
 }
 
diff --git a/src/include/86box/chipset.h b/src/include/86box/chipset.h
index bdc9497e3..3e27c3a8b 100644
--- a/src/include/86box/chipset.h
+++ b/src/include/86box/chipset.h
@@ -95,9 +95,7 @@ extern const device_t	sis_85c461_device;
 extern const device_t	sis_85c471_device;
 extern const device_t	sis_85c496_device;
 extern const device_t	sis_85c496_ls486e_device;
-#if defined(DEV_BRANCH) && defined(USE_SIS_85C50X)
 extern const device_t	sis_85c50x_device;
-#endif
 
 /* ST */
 #if defined(DEV_BRANCH) && defined(USE_STPC)
diff --git a/src/include/86box/keyboard.h b/src/include/86box/keyboard.h
index 3785a8f6d..fe0593b19 100644
--- a/src/include/86box/keyboard.h
+++ b/src/include/86box/keyboard.h
@@ -102,6 +102,7 @@ extern void	keyboard_set_states(uint8_t cl, uint8_t nl, uint8_t sl);
 extern int	keyboard_recv(uint16_t key);
 extern int	keyboard_isfsexit(void);
 extern int	keyboard_ismsexit(void);
+extern void	keyboard_set_is_amstrad(int ams);
 
 extern void	keyboard_at_adddata_keyboard_raw(uint8_t val);
 extern void	keyboard_at_adddata_mouse(uint8_t val);
diff --git a/src/include/86box/machine.h b/src/include/86box/machine.h
index a20cc2379..e57844970 100644
--- a/src/include/86box/machine.h
+++ b/src/include/86box/machine.h
@@ -301,6 +301,7 @@ extern int	machine_at_403tg_init(const machine_t *);
 extern int	machine_at_pc330_6571_init(const machine_t *);
 
 extern int	machine_at_sis401_init(const machine_t *);
+extern int	machine_at_av4_init(const machine_t *);
 extern int	machine_at_valuepoint433_init(const machine_t *);
 
 extern int	machine_at_vli486sv2g_init(const machine_t *);
@@ -354,10 +355,8 @@ extern int	machine_at_excalibur_init(const machine_t *);
 
 extern int	machine_at_batman_init(const machine_t *);
 extern int	machine_at_ambradp60_init(const machine_t *);
-#if defined(DEV_BRANCH) && defined(USE_DELLS4)
 extern int	machine_at_dellxp60_init(const machine_t *);
 extern int	machine_at_opti560l_init(const machine_t *);
-#endif
 extern int	machine_at_valuepointp60_init(const machine_t *);
 extern int	machine_at_p5mp3_init(const machine_t *);
 extern int	machine_at_pb520r_init(const machine_t *);
@@ -376,11 +375,9 @@ extern int	machine_at_vectra54_init(const machine_t *);
 extern int	machine_at_powermate_v_init(const machine_t *);
 extern int	machine_at_acerv30_init(const machine_t *);
 
-#if defined(DEV_BRANCH) && defined(USE_SIS_85C50X)
 extern int	machine_at_p5sp4_init(const machine_t *);
 extern int	machine_at_p54sp4_init(const machine_t *);
 extern int	machine_at_sq588_init(const machine_t *);
-#endif
 
 #ifdef EMU_DEVICE_H
 extern const device_t	*at_endeavor_get_device(void);
diff --git a/src/include/86box/vid_svga.h b/src/include/86box/vid_svga.h
index 64e9aab1b..5d3d99bd3 100644
--- a/src/include/86box/vid_svga.h
+++ b/src/include/86box/vid_svga.h
@@ -22,6 +22,7 @@
 #define	FLAG_ADDR_BY8		2
 #define FLAG_EXT_WRITE		4
 #define FLAG_LATCH8		8
+#define FLAG_NOSKEW		16
 
 
 typedef struct {
diff --git a/src/machine/m_amstrad.c b/src/machine/m_amstrad.c
index ec0bff6ec..44904c0c8 100644
--- a/src/machine/m_amstrad.c
+++ b/src/machine/m_amstrad.c
@@ -1715,8 +1715,13 @@ vid_close_200(void *priv)
 {
     amsvid_t *vid = (amsvid_t *)priv;
 
-    free(vid->cga.vram);
-    free(vid->mda.vram);
+    if (vid->cga.vram != vid->mda.vram) {
+	free(vid->cga.vram);
+	free(vid->mda.vram);
+    } else
+	free(vid->cga.vram);
+
+    vid->cga.vram = vid->mda.vram = NULL;
 
     free(vid);
 }
@@ -2111,8 +2116,7 @@ kbd_adddata(uint16_t val)
 static void
 kbd_adddata_ex(uint16_t val)
 {
-    kbd_adddata(val);
-    // kbd_adddata_process(val, kbd_adddata);
+    kbd_adddata_process(val, kbd_adddata);
 }
 
 
@@ -2495,6 +2499,7 @@ machine_amstrad_init(const machine_t *model, int type)
     keyboard_set_table(scancode_xt);
     keyboard_send = kbd_adddata_ex;
     keyboard_scan = 1;
+    keyboard_set_is_amstrad(1);
 
     io_sethandler(0x0078, 2,
 		  ms_read, NULL, NULL, ms_write, NULL, NULL, ams);
diff --git a/src/machine/m_at_386dx_486.c b/src/machine/m_at_386dx_486.c
index 0a14926bf..74ca503d5 100644
--- a/src/machine/m_at_386dx_486.c
+++ b/src/machine/m_at_386dx_486.c
@@ -102,6 +102,27 @@ machine_at_sis401_init(const machine_t *model)
     return ret;
 }
 
+
+int
+machine_at_av4_init(const machine_t *model)
+{
+    int ret;
+
+    ret = bios_load_linear(L"roms/machines/av4/amibios_486dx_isa_bios_aa4025963.bin",
+			   0x000f0000, 65536, 0);
+
+    if (bios_only || !ret)
+	return ret;
+
+    machine_at_common_ide_init(model);
+    device_add(&sis_85c460_device);
+    device_add(&keyboard_at_ami_device);
+    device_add(&fdc_at_device);
+
+    return ret;
+}
+
+
 int
 machine_at_valuepoint433_init(const machine_t *model)	// hangs without the PS/2 mouse
 {
@@ -121,6 +142,7 @@ machine_at_valuepoint433_init(const machine_t *model)	// hangs without the PS/2
     return ret;
 }
 
+
 int
 machine_at_ecs386_init(const machine_t *model)
 {
diff --git a/src/machine/m_at_socket4_5.c b/src/machine/m_at_socket4_5.c
index 2cbdaa0d1..84c6e97d2 100644
--- a/src/machine/m_at_socket4_5.c
+++ b/src/machine/m_at_socket4_5.c
@@ -122,7 +122,6 @@ machine_at_batman_init(const machine_t *model)
 }
 
 
-#if defined(DEV_BRANCH) && defined(USE_DELLS4)
 int
 machine_at_dellxp60_init(const machine_t *model)
 {
@@ -184,7 +183,6 @@ machine_at_opti560l_init(const machine_t *model)
 
     return ret;
 }
-#endif 
 
 
 int
@@ -648,7 +646,6 @@ machine_at_acerv30_init(const machine_t *model)
 }
 
 
-#if defined(DEV_BRANCH) && defined(USE_SIS_85C50X)
 static void
 machine_at_sp4_common_init(const machine_t *model)
 {
@@ -737,4 +734,3 @@ machine_at_sq588_init(const machine_t *model)
 
     return ret;
 }
-#endif
diff --git a/src/machine/m_tandy.c b/src/machine/m_tandy.c
index 470cd099c..fbfb6054d 100644
--- a/src/machine/m_tandy.c
+++ b/src/machine/m_tandy.c
@@ -298,11 +298,11 @@ static const scancode scancode_tandy[512] = {
     { {0},             {0} }, { {0},             {0} },	/*140*/
     { {0},             {0} }, { {0},             {0} },
     { {0x46, 0}, {0xc6, 0} }, { {0x47, 0}, {0xc7, 0} },	/*144*/
-    { {0x48, 0}, {0xc8, 0} }, { {0x49, 0}, {0xc9, 0} },
-    { {0},             {0} }, { {0x4b, 0}, {0xcb, 0} },	/*148*/
-    { {0},             {0} }, { {0x4d, 0}, {0xcd, 0} },
+    { {0x29, 0}, {0xa9, 0} }, { {0x49, 0}, {0xc9, 0} },
+    { {0},             {0} }, { {0x2b, 0}, {0xab, 0} },	/*148*/
+    { {0},             {0} }, { {0x4e, 0}, {0xce, 0} },
     { {0},             {0} }, { {0x4f, 0}, {0xcf, 0} },	/*14c*/
-    { {0x50, 0}, {0xd0, 0} }, { {0x51, 0}, {0xd1, 0} },
+    { {0x4a, 0}, {0xca, 0} }, { {0x51, 0}, {0xd1, 0} },
     { {0x52, 0}, {0xd2, 0} }, { {0x53, 0}, {0xd3, 0} },	/*150*/
     { {0},             {0} }, { {0},             {0} },
     { {0},             {0} }, { {0},             {0} },	/*154*/
diff --git a/src/machine/m_xt_olivetti.c b/src/machine/m_xt_olivetti.c
index a52588ce0..a2f3d2725 100644
--- a/src/machine/m_xt_olivetti.c
+++ b/src/machine/m_xt_olivetti.c
@@ -118,6 +118,7 @@ m24_log(const char *fmt, ...)
 #define m24_log(fmt, ...)
 #endif
 
+
 static void
 m24_kbd_poll(void *priv)
 {
@@ -171,9 +172,8 @@ m24_kbd_write(uint16_t port, uint8_t val, void *priv)
 #endif
 
 #if 0
-    if (ram[8] == 0xc3) {
+    if (ram[8] == 0xc3)
 	output = 3;
-    }
 #endif
     switch (port) {
 	case 0x60:
@@ -242,6 +242,7 @@ m24_kbd_write(uint16_t port, uint8_t val, void *priv)
     }
 }
 
+
 static uint8_t
 m24_kbd_read(uint16_t port, void *priv)
 {
@@ -279,11 +280,13 @@ m24_kbd_read(uint16_t port, void *priv)
     return(ret);
 }
 
+
 static void
 m24_kbd_close(void *priv)
 {
-	olim24_kbd_t *kbd = (olim24_kbd_t *)priv;
-	/* Stop the timer. */
+    olim24_kbd_t *kbd = (olim24_kbd_t *)priv;
+
+    /* Stop the timer. */
     timer_disable(&kbd->send_delay_timer);
  
     /* Disable scanning. */
@@ -293,12 +296,13 @@ m24_kbd_close(void *priv)
 
     io_removehandler(0x0060, 2,
 		     m24_kbd_read, NULL, NULL, m24_kbd_write, NULL, NULL, kbd);
-	io_removehandler(0x0064, 1,
+    io_removehandler(0x0064, 1,
 		     m24_kbd_read, NULL, NULL, m24_kbd_write, NULL, NULL, kbd);
 
     free(kbd);
 }
 
+
 static void
 m24_kbd_reset(void *priv)
 {
@@ -319,6 +323,7 @@ m24_kbd_reset(void *priv)
     m24_kbd->scan[6] = 0x50;   
 }
 
+
 static int
 ms_poll(int x, int y, int z, int b, void *priv)
 {
@@ -401,10 +406,12 @@ ms_poll(int x, int y, int z, int b, void *priv)
     return(0);
 }
 
+
 static void
-m24_kbd_init(olim24_kbd_t *kbd){
+m24_kbd_init(olim24_kbd_t *kbd)
+{
 	
-	/* Initialize the keyboard. */
+    /* Initialize the keyboard. */
     io_sethandler(0x0060, 2,
 		  m24_kbd_read, NULL, NULL, m24_kbd_write, NULL, NULL, kbd);
     io_sethandler(0x0064, 1,
@@ -418,152 +425,160 @@ m24_kbd_init(olim24_kbd_t *kbd){
     mouse_set_poll(ms_poll, kbd);
 
     keyboard_set_table(scancode_xt);
-
+    keyboard_set_is_amstrad(0);
 }
 
+
 static void
 m19_vid_out(uint16_t addr, uint8_t val, void *priv)
 {
-	olim19_vid_t *vid = (olim19_vid_t *)priv;
-	int oldmode = vid->mode;
-	
-	/* activating plantronics mode */
-	if (addr == 0x3dd){	
-		/* already in graphics mode */
-		if ((val & 0x30) && (vid->ogc.cga.cgamode & 0x2)) {
-			vid->mode = PLANTRONICS_MODE;
-		} else { 
-			vid->mode = OLIVETTI_OGC_MODE;
-}
-	/* setting graphics mode */
-	} else if (addr == 0x3d8) {
-		if ((val & 0x2) && (vid->colorplus.control & 0x30)){
-			vid->mode = PLANTRONICS_MODE;
-		} else {
-			vid->mode = OLIVETTI_OGC_MODE;
-		}
+    olim19_vid_t *vid = (olim19_vid_t *)priv;
+    int oldmode = vid->mode;
+
+    /* activating plantronics mode */
+    if (addr == 0x3dd) {
+	/* already in graphics mode */
+	if ((val & 0x30) && (vid->ogc.cga.cgamode & 0x2))
+		vid->mode = PLANTRONICS_MODE;
+	else
+		vid->mode = OLIVETTI_OGC_MODE;
+    /* setting graphics mode */
+    } else if (addr == 0x3d8) {
+	if ((val & 0x2) && (vid->colorplus.control & 0x30))
+		vid->mode = PLANTRONICS_MODE;
+	else
+		vid->mode = OLIVETTI_OGC_MODE;
+    }
+    /* video mode changed */
+    if (oldmode != vid->mode) {
+	/* activate Plantronics emulation */
+	if (vid->mode == PLANTRONICS_MODE){
+		timer_disable(&vid->ogc.cga.timer);
+		timer_set_delay_u64(&vid->colorplus.cga.timer, 0);
+	/* return to OGC mode */
+	} else {
+		timer_disable(&vid->colorplus.cga.timer);
+		timer_set_delay_u64(&vid->ogc.cga.timer, 0);
 	}
-	/* video mode changed */
-	if(oldmode != vid->mode){
-		/* activate Plantronics emulation */
-		if (vid->mode == PLANTRONICS_MODE){
-			timer_disable(&vid->ogc.cga.timer);
-			timer_set_delay_u64(&vid->colorplus.cga.timer, 0);
-		/* return to OGC mode */
-		} else {
-			timer_disable(&vid->colorplus.cga.timer);
-			timer_set_delay_u64(&vid->ogc.cga.timer, 0);
-		}
-		colorplus_recalctimings(&vid->colorplus);
-		ogc_recalctimings(&vid->ogc);
-	}
-	colorplus_out(addr, val, &vid->colorplus);
-	ogc_out(addr, val, &vid->ogc);
+
+	colorplus_recalctimings(&vid->colorplus);
+	ogc_recalctimings(&vid->ogc);
+    }
+
+    colorplus_out(addr, val, &vid->colorplus);
+    ogc_out(addr, val, &vid->ogc);
 }
 
+
 static uint8_t
 m19_vid_in(uint16_t addr, void *priv)
 {
-	olim19_vid_t *vid = (olim19_vid_t *)priv;
-	if ( vid->mode == PLANTRONICS_MODE ) {
-		return colorplus_in(addr, &vid->colorplus);
-	} else {
-		return ogc_in(addr, &vid->ogc);
+    olim19_vid_t *vid = (olim19_vid_t *)priv;
+
+    if (vid->mode == PLANTRONICS_MODE)
+	return colorplus_in(addr, &vid->colorplus);
+    else
+	return ogc_in(addr, &vid->ogc);
 }
 
-}
 
 static uint8_t
 m19_vid_read(uint32_t addr, void *priv)
 {
-	olim19_vid_t *vid = (olim19_vid_t *)priv;
-	vid->colorplus.cga.mapping = vid->ogc.cga.mapping;
-	if ( vid->mode == PLANTRONICS_MODE ) {
-		return colorplus_read(addr, &vid->colorplus);
-	} else {
-		return ogc_read(addr, &vid->ogc);
-}
+    olim19_vid_t *vid = (olim19_vid_t *)priv;
+
+    vid->colorplus.cga.mapping = vid->ogc.cga.mapping;
+    if (vid->mode == PLANTRONICS_MODE)
+	return colorplus_read(addr, &vid->colorplus);
+    else
+	return ogc_read(addr, &vid->ogc);
 }
 
+
 static void
 m19_vid_write(uint32_t addr, uint8_t val, void *priv)
 {
-	olim19_vid_t *vid = (olim19_vid_t *)priv;
-	colorplus_write(addr, val, &vid->colorplus);
-	ogc_write(addr, val, &vid->ogc);
+    olim19_vid_t *vid = (olim19_vid_t *)priv;
+
+    colorplus_write(addr, val, &vid->colorplus);
+    ogc_write(addr, val, &vid->ogc);
 }
 
 
 static void
 m19_vid_close(void *priv)
 {
-	olim19_vid_t *vid = (olim19_vid_t *)priv;
-	free(vid->ogc.cga.vram);
+    olim19_vid_t *vid = (olim19_vid_t *)priv;
+
+    free(vid->ogc.cga.vram);
     free(vid->colorplus.cga.vram);
-	free(vid);
+    free(vid);
 }
 
+
 static void
 m19_vid_speed_changed(void *priv)
 {
-	olim19_vid_t *vid = (olim19_vid_t *)priv;
-	colorplus_recalctimings(&vid->colorplus);
-	ogc_recalctimings(&vid->ogc);
+    olim19_vid_t *vid = (olim19_vid_t *)priv;
+
+    colorplus_recalctimings(&vid->colorplus);
+    ogc_recalctimings(&vid->ogc);
 }
 
+
 static void
-m19_vid_init(olim19_vid_t *vid){
+m19_vid_init(olim19_vid_t *vid)
+{
+    /* int display_type; */
+    vid->mode = OLIVETTI_OGC_MODE;
 
-	//int display_type;
-	vid->mode = OLIVETTI_OGC_MODE;
+    video_inform(VIDEO_FLAG_TYPE_CGA, &timing_m19_vid);
 
-	video_inform(VIDEO_FLAG_TYPE_CGA, &timing_m19_vid);
+    /* display_type = device_get_config_int("display_type"); */
 
-	//display_type = device_get_config_int("display_type");
-    
-	/* OGC emulation part begin */
-	loadfont_ex(L"roms/machines/olivetti_m19/BIOS.BIN", 1, 90);
-	/* composite is not working yet */
-	vid->ogc.cga.composite = 0; // (display_type != CGA_RGB);
-    //vid->ogc.cga.snow_enabled = device_get_config_int("snow_enabled");
-	
-	vid->ogc.cga.vram = malloc(0x8000);
+    /* OGC emulation part begin */
+    loadfont_ex(L"roms/machines/olivetti_m19/BIOS.BIN", 1, 90);
+    /* composite is not working yet */
+    vid->ogc.cga.composite = 0; // (display_type != CGA_RGB);
+    /* vid->ogc.cga.snow_enabled = device_get_config_int("snow_enabled"); */
 
-	//cga_comp_init(vid->ogc.cga.revision);
-    
-	//vid->ogc.cga.rgb_type = device_get_config_int("rgb_type");
-    //cga_palette = (vid->ogc.cga.rgb_type << 1);
+    vid->ogc.cga.vram = malloc(0x8000);
+
+    /* cga_comp_init(vid->ogc.cga.revision); */
+
+    /* vid->ogc.cga.rgb_type = device_get_config_int("rgb_type"); */
+    /* cga_palette = (vid->ogc.cga.rgb_type << 1); */
     cga_palette = 0;
-	cgapal_rebuild();
-	ogc_mdaattr_rebuild();
+    cgapal_rebuild();
+    ogc_mdaattr_rebuild();
 
-	/* color display */
-	// if (device_get_config_int("rgb_type")==0 || device_get_config_int("rgb_type") == 4) 
-	vid->ogc.mono_display = 1;
-	// else
-	// 	vid->ogc.mono_display = 1;    
-	/* OGC emulation part end */
-	
-	/* Plantronics emulation part begin*/
-	/* composite is not working yet */
-	vid->colorplus.cga.composite = 0; //(display_type != CGA_RGB);
-    // vid->colorplus.cga.snow_enabled = device_get_config_int("snow_enabled");
+    /* color display */
+    /* if (device_get_config_int("rgb_type")==0 || device_get_config_int("rgb_type") == 4)  */
+    vid->ogc.mono_display = 1;
+    /* else */
+    /* 	vid->ogc.mono_display = 1;     */
+    /* OGC emulation part end */
+
+    /* Plantronics emulation part begin*/
+    /* composite is not working yet */
+    vid->colorplus.cga.composite = 0; //(display_type != CGA_RGB);
+    /* vid->colorplus.cga.snow_enabled = device_get_config_int("snow_enabled"); */
 
     vid->colorplus.cga.vram = malloc(0x8000);
-                
-	//vid->colorplus.cga.cgamode = 0x1;
-	/* Plantronics emulation part end*/
 
-	timer_add(&vid->ogc.cga.timer, ogc_poll, &vid->ogc, 1);
-	timer_add(&vid->colorplus.cga.timer, colorplus_poll, &vid->colorplus, 1);
-	timer_disable(&vid->colorplus.cga.timer);
-	mem_mapping_add(&vid->ogc.cga.mapping, 0xb8000, 0x08000, m19_vid_read, NULL, NULL, m19_vid_write, NULL, NULL,  NULL, MEM_MAPPING_EXTERNAL, vid);
-	io_sethandler(0x03d0, 0x0010, m19_vid_in, NULL, NULL, m19_vid_out, NULL, NULL, vid);
-	
-	vid->mode = OLIVETTI_OGC_MODE;
-	
+    /* vid->colorplus.cga.cgamode = 0x1; */
+    /* Plantronics emulation part end*/
+
+    timer_add(&vid->ogc.cga.timer, ogc_poll, &vid->ogc, 1);
+    timer_add(&vid->colorplus.cga.timer, colorplus_poll, &vid->colorplus, 1);
+    timer_disable(&vid->colorplus.cga.timer);
+    mem_mapping_add(&vid->ogc.cga.mapping, 0xb8000, 0x08000, m19_vid_read, NULL, NULL, m19_vid_write, NULL, NULL,  NULL, MEM_MAPPING_EXTERNAL, vid);
+    io_sethandler(0x03d0, 0x0010, m19_vid_in, NULL, NULL, m19_vid_out, NULL, NULL, vid);
+
+    vid->mode = OLIVETTI_OGC_MODE;
 }
 
+
 const device_t m24_kbd_device = {
     "Olivetti M24 keyboard and mouse",
     0,
@@ -590,11 +605,13 @@ m19_get_device(void)
     return &m19_vid_device;
 }
 
+
 static uint8_t
 m24_read(uint16_t port, void *priv)
 {
-	uint8_t ret = 0x00;
-	int i, fdd_count = 0; 
+    uint8_t ret = 0x00;
+    int i, fdd_count = 0; 
+
     switch (port) {
 	/* 
 	 * port 66:
@@ -610,7 +627,7 @@ m24_read(uint16_t port, void *priv)
 		/* Switch 5 - 8087 present */
 		if (hasfpu)
 			ret |= 0x10;
-	/* 
+		/* 
 		 * Switches 1, 2, 3, 4 - installed memory 
 		 * Switch 8 - Use memory bank 1
 		 */
@@ -650,10 +667,9 @@ m24_read(uint16_t port, void *priv)
 	 */
 	case 0x67:
 		for (i = 0; i < FDD_NUM; i++) {
-            if (fdd_get_flags(i)) {
+			if (fdd_get_flags(i))
 				fdd_count++;
 		}
-    }
 
 		/* Switches 7, 8 - floppy drives. */
 		if (!fdd_count)
@@ -674,17 +690,19 @@ m24_read(uint16_t port, void *priv)
 		
 		/* Switch 2 - Set fast startup */
 		ret |= 0x2;
-}
+    }
 
     return(ret);
 }
 
+
 const device_t *
 m24_get_device(void)
 {
     return &ogc_m24_device;
 }
 
+
 int
 machine_xt_olim24_init(const machine_t *model)
 {
@@ -708,22 +726,21 @@ machine_xt_olim24_init(const machine_t *model)
     machine_common_init(model);
     device_add(&fdc_xt_device);
 
-	//address 66-67 = mainboard dip-switch settings
-	io_sethandler(0x0066, 2, m24_read, NULL, NULL, NULL, NULL, NULL, NULL);
+    /* Address 66-67 = mainboard dip-switch settings */
+    io_sethandler(0x0066, 2, m24_read, NULL, NULL, NULL, NULL, NULL, NULL);
 
-	m24_kbd_init(m24_kbd);
-	device_add_ex(&m24_kbd_device, m24_kbd);
+    m24_kbd_init(m24_kbd);
+    device_add_ex(&m24_kbd_device, m24_kbd);
 
-	/* FIXME: make sure this is correct?? */
+    /* FIXME: make sure this is correct?? */
     device_add(&at_nvr_device);
 
     if (joystick_type)
-		device_add(&gameport_device);
+	device_add(&gameport_device);
 
     nmi_init();
 
-    
-	return ret;
+    return ret;
 }
 
 /*
@@ -746,10 +763,10 @@ machine_xt_olim240_init(const machine_t *model)
 
 	pit_ctr_set_out_func(&pit->counters[1], pit_refresh_timer_xt);
 
-	/* 
-	 * port 60: should return jumper settings only under unknown conditions
-	 * SWB on mainboard (off=1)
-	 * bit 7 - use BIOS HD on mainboard (on) / on controller (off)
+    /* 
+     * port 60: should return jumper settings only under unknown conditions
+     * SWB on mainboard (off=1)
+     * bit 7 - use BIOS HD on mainboard (on) / on controller (off)
      * bit 6 - use OCG/CGA display adapter (on) / other display adapter (off)
      */
     device_add(&keyboard_at_olivetti_device);
@@ -757,11 +774,11 @@ machine_xt_olim240_init(const machine_t *model)
     /* FIXME: make sure this is correct?? */
     device_add(&at_nvr_device);
 
-	if (fdc_type == FDC_INTERNAL)	
-		device_add(&fdc_xt_device);
+    if (fdc_type == FDC_INTERNAL)	
+	device_add(&fdc_xt_device);
 
-	if (joystick_type)
-		device_add(&gameport_device);
+    if (joystick_type)
+	device_add(&gameport_device);
 
     nmi_init();
 
@@ -787,19 +804,19 @@ machine_xt_olim19_init(const machine_t *model)
 
     olim19_vid_t *vid;
 
-	/* do not move memory allocation elsewhere */
-	vid = (olim19_vid_t *)malloc(sizeof(olim19_vid_t));
-	memset(vid, 0x00, sizeof(olim19_vid_t));
+    /* Do not move memory allocation elsewhere. */
+    vid = (olim19_vid_t *)malloc(sizeof(olim19_vid_t));
+    memset(vid, 0x00, sizeof(olim19_vid_t));
 	
     machine_common_init(model);
     device_add(&fdc_xt_device);
 
-	m19_vid_init(vid);
-	device_add_ex(&m19_vid_device, vid);
+    m19_vid_init(vid);
+    device_add_ex(&m19_vid_device, vid);
 
-	device_add(&keyboard_xt_olivetti_device);
-	
-	nmi_init();
+    device_add(&keyboard_xt_olivetti_device);
+
+    nmi_init();
 
     return ret;
 
diff --git a/src/machine/machine_table.c b/src/machine/machine_table.c
index f8295ffd9..e69b102b7 100644
--- a/src/machine/machine_table.c
+++ b/src/machine/machine_table.c
@@ -187,6 +187,7 @@ const machine_t machines[] = {
     { "[OPTi 802G] IBM PC 330 (type 6571)",	"pc330_6571",		MACHINE_TYPE_486,		CPU_PKG_SOCKET3_PC330, 0, 25000000, 33333333, 0, 0, 2.0, 3.0,							MACHINE_VLB | MACHINE_BUS_PS2 | MACHINE_IDE,					 1024, 65536, 1024, 127,	   machine_at_pc330_6571_init, NULL			},
     { "[OPTi 895] Jetway J-403TG",		"403tg",		MACHINE_TYPE_486,		CPU_PKG_SOCKET3, 0, 0, 0, 0, 0, 0, 0,										MACHINE_VLB,									 1024, 65536, 1024, 127,	        machine_at_403tg_init, NULL			},
     { "[SiS 401] AMI 486 Clone",		"sis401",		MACHINE_TYPE_486,		CPU_PKG_SOCKET3, 0, 0, 0, 0, 0, 0, 0,										MACHINE_AT | MACHINE_IDE,							 1024, 65536, 1024, 127,	       machine_at_sis401_init, NULL			},
+    { "[SiS 460] ABIT AV4",			"av4",			MACHINE_TYPE_486,		CPU_PKG_SOCKET3, 0, 0, 0, 0, 0, 0, 0,										MACHINE_VLB | MACHINE_IDE,							 1024, 65536, 1024, 127,		  machine_at_av4_init, NULL			},
     { "[SiS 461] IBM PS/ValuePoint 433DX/Si",	"valuepoint433",	MACHINE_TYPE_486,		CPU_PKG_SOCKET3, 0, 0, 0, 0, 0, 0, 0,										MACHINE_AT | MACHINE_BUS_PS2 | MACHINE_IDE,					 1024, 65536, 1024, 127,	machine_at_valuepoint433_init, NULL			},
     { "[SiS 471] AMI 486 Clone",		"ami471",		MACHINE_TYPE_486,		CPU_PKG_SOCKET3, 0, 0, 0, 0, 0, 0, 0,										MACHINE_VLB | MACHINE_IDE,							 1024, 65536, 1024, 127,	       machine_at_ami471_init, NULL			},
     { "[SiS 471] AMI WinBIOS 486 clone",	"win471",		MACHINE_TYPE_486,		CPU_PKG_SOCKET3, 0, 0, 0, 0, 0, 0, 0,										MACHINE_VLB | MACHINE_IDE,							 1024, 65536, 1024, 127,	       machine_at_win471_init, NULL			},
@@ -230,10 +231,8 @@ const machine_t machines[] = {
     /* Socket 4 machines */
     /* 430LX */
     { "[i430LX] ASUS P/I-P5MP3",		"p5mp3",		MACHINE_TYPE_SOCKET4,		CPU_PKG_SOCKET4, 0, 60000000, 66666667, 0, 0, MACHINE_MULTIPLIER_FIXED,						MACHINE_PCI | MACHINE_BUS_PS2 | MACHINE_IDE,		 			 2048, 196608, 2048, 127,	        machine_at_p5mp3_init, NULL			},
-#if defined(DEV_BRANCH) && defined(USE_DELLS4)
     { "[i430LX] Dell Dimension XPS P60",	"dellxp60",		MACHINE_TYPE_SOCKET4,		CPU_PKG_SOCKET4, 0, 60000000, 66666667, 0, 0, MACHINE_MULTIPLIER_FIXED,						MACHINE_PCI | MACHINE_BUS_PS2 | MACHINE_IDE,					 2048, 131072, 2048, 127,	     machine_at_dellxp60_init, NULL			},
     { "[i430LX] Dell OptiPlex 560/L",		"opti560l",		MACHINE_TYPE_SOCKET4,		CPU_PKG_SOCKET4, 0, 60000000, 66666667, 0, 0, MACHINE_MULTIPLIER_FIXED,						MACHINE_PCI | MACHINE_BUS_PS2 | MACHINE_IDE_DUAL,				 2048, 131072, 2048, 127,	     machine_at_opti560l_init, NULL			},
-#endif
     { "[i430LX] IBM Ambra DP60 PCI",		"ambradp60",		MACHINE_TYPE_SOCKET4,		CPU_PKG_SOCKET4, 0, 60000000, 66666667, 0, 0, MACHINE_MULTIPLIER_FIXED,						MACHINE_PCI | MACHINE_BUS_PS2 | MACHINE_IDE_DUAL,				 2048, 131072, 2048, 127,	    machine_at_ambradp60_init, NULL			},
     { "[i430LX] IBM PS/ValuePoint P60",		"valuepointp60",	MACHINE_TYPE_SOCKET4,		CPU_PKG_SOCKET4, 0, 60000000, 66666667, 0, 0, MACHINE_MULTIPLIER_FIXED,						MACHINE_PCI | MACHINE_BUS_PS2 | MACHINE_IDE_DUAL,		 		 2048, 131072, 2048, 127,	machine_at_valuepointp60_init, NULL			},
     { "[i430LX] Intel Premiere/PCI",		"revenge",		MACHINE_TYPE_SOCKET4,		CPU_PKG_SOCKET4, 0, 60000000, 66666667, 0, 0, MACHINE_MULTIPLIER_FIXED,						MACHINE_PCI | MACHINE_BUS_PS2 | MACHINE_IDE_DUAL,				 2048, 131072, 2048, 127,	       machine_at_batman_init, NULL			},
@@ -244,9 +243,7 @@ const machine_t machines[] = {
     { "[OPTi 597] AMI Excalibur VLB",		"excalibur",		MACHINE_TYPE_SOCKET4,		CPU_PKG_SOCKET4, 0, 60000000, 66666667, 0, 0, MACHINE_MULTIPLIER_FIXED,						MACHINE_VLB | MACHINE_IDE,							 2048,  65536, 2048, 127,	    machine_at_excalibur_init, NULL			},
 
     /* SiS 85C50x */
-    #if defined(DEV_BRANCH) && defined(USE_SIS_85C50X)
     { "[SiS 85C50x] ASUS PCI/I-P5SP4",		"p5sp4",		MACHINE_TYPE_SOCKET4,		CPU_PKG_SOCKET4, 0, 60000000, 66666667, 0, 0, MACHINE_MULTIPLIER_FIXED,						MACHINE_PCI | MACHINE_BUS_PS2 | MACHINE_IDE_DUAL,				 8192, 131072, 8192, 127,	      machine_at_p5sp4_init, NULL			},
-    #endif
 
     /* Socket 5 machines */
     /* 430NX */
@@ -263,10 +260,8 @@ const machine_t machines[] = {
     { "[i430FX] PC Partner MB500N",		"mb500n",		MACHINE_TYPE_SOCKET5,		CPU_PKG_SOCKET5_7, 0, 50000000, 66666667, 3380, 3520, 1.5, 3.0,							MACHINE_PCI | MACHINE_IDE_DUAL,							 8192, 131072, 8192, 127,	       machine_at_mb500n_init, NULL			},
 
     /* SiS 85C50x */
-    #if defined(DEV_BRANCH) && defined(USE_SIS_85C50X)
     { "[SiS 85C50x] ASUS PCI/I-P54SP4",		"p54sp4",		MACHINE_TYPE_SOCKET5,		CPU_PKG_SOCKET5_7, 0, 50000000, 66666667, 3380, 3520, 1.5, 2.0,							MACHINE_PCI | MACHINE_BUS_PS2 | MACHINE_IDE_DUAL,				 8192, 131072, 8192, 127,	     machine_at_p54sp4_init, NULL			},
     { "[SiS 85C50x] BCM SQ-588",		"sq588",		MACHINE_TYPE_SOCKET5,		CPU_PKG_SOCKET5_7, 0, 50000000, 66666667, 3380, 3520, 1.5, 2.0,							MACHINE_PCI | MACHINE_BUS_PS2 | MACHINE_IDE_DUAL,				 8192, 131072, 8192, 127,	      machine_at_sq588_init, NULL			},
-    #endif
     
     /* Socket 7 machines */
     /* 430FX */
diff --git a/src/video/vid_et4000w32.c b/src/video/vid_et4000w32.c
index 2c04b454e..b3eb235bd 100644
--- a/src/video/vid_et4000w32.c
+++ b/src/video/vid_et4000w32.c
@@ -1312,6 +1312,7 @@ void *et4000w32p_init(const device_t *info)
 
 			et4000->svga.clock_gen = et4000->svga.ramdac;
 			et4000->svga.getclock = stg_getclock;
+			et4000->svga.adv_flags |= FLAG_NOSKEW;
 			break;
 
 		case ET4000W32_DIAMOND:
diff --git a/src/video/vid_svga.c b/src/video/vid_svga.c
index 0e1511af4..0298c3f36 100644
--- a/src/video/vid_svga.c
+++ b/src/video/vid_svga.c
@@ -445,7 +445,7 @@ svga_recalctimings(svga_t *svga)
 
     svga->interlace = 0;
 
-    svga->ma_latch = ((svga->crtc[0xc] << 8) | svga->crtc[0xd]) + ((svga->crtc[8] & 0x60) >> 5);
+    svga->ma_latch = ((svga->crtc[0xc] << 8) | svga->crtc[0xd]);
     svga->ca_adj = 0;
     
     svga->rowcount = svga->crtc[9] & 31;    
@@ -459,6 +459,8 @@ svga_recalctimings(svga_t *svga)
 			svga->hdisp *= (svga->seqregs[1] & 1) ? 16 : 18;
 		} else {
 			svga->render = svga_render_text_80;
+			if (!(svga->adv_flags & FLAG_NOSKEW))
+				svga->ma_latch += ((svga->crtc[8] & 0x60) >> 5);
 			svga->hdisp *= (svga->seqregs[1] & 1) ? 8 : 9;
 		}
 		svga->hdisp_old = svga->hdisp;
diff --git a/src/win/Makefile.mingw b/src/win/Makefile.mingw
index 815e109e1..9cf52250d 100644
--- a/src/win/Makefile.mingw
+++ b/src/win/Makefile.mingw
@@ -75,9 +75,6 @@ ifeq ($(DEV_BUILD), y)
  ifndef SIO_DETECT
   SIO_DETECT	:= y
  endif
- ifndef USE_SIS_85C50X
-  USE_SIS_85C50X	:= y
- endif
  ifndef STPC
   STPC		:= y
  endif
@@ -99,9 +96,6 @@ ifeq ($(DEV_BUILD), y)
  ifndef USE_VECT486VL
   USE_VECT486VL	:= y
  endif
- ifndef USE_DELLS4
-  USE_DELLS4	:= y
- endif
 else
  ifndef DEBUG
   DEBUG		:= n
@@ -151,9 +145,6 @@ else
  ifndef SIO_DETECT
   SIO_DETECT	:= n
  endif
- ifndef USE_SIS_85C50X
-  USE_SIS_85C50X	:= n
- endif
  ifndef STPC
   STPC		:= y
  endif
@@ -175,9 +166,6 @@ else
  ifndef USE_VECT486VL
   USE_VECT486VL	:= n
  endif
- ifndef USE_DELLS4
-  USE_DELLS4	:= n
- endif
 endif
 
 # Defaults for several build options (possibly defined in a chained file.)
@@ -549,11 +537,6 @@ OPTS		+= -DUSE_SIO_DETECT
 DEVBROBJ	+= sio_detect.o
 endif
 
-ifeq ($(USE_SIS_85C50X), y)
-OPTS		+= -DUSE_SIS_85C50X
-DEVBROBJ	+= sis_85c50x.o
-endif
-
 ifeq ($(STPC), y)
 OPTS		+= -DUSE_STPC
 DEVBROBJ	+= stpc.o
@@ -581,10 +564,6 @@ ifeq ($(USE_VECT486VL), y)
 OPTS		+= -DUSE_VECT486VL
 endif
 
-ifeq ($(USE_DELLS4), y)
-OPTS		+= -DUSE_DELLS4
-endif
-
 endif
 
 
@@ -617,7 +596,7 @@ CPUOBJ		:= cpu.o cpu_table.o \
 CHIPSETOBJ	:= acc2168.o cs8230.o ali1429.o headland.o intel_82335.o cs4031.o \
 		    intel_420ex.o intel_4x0.o intel_sio.o intel_piix.o ioapic.o \
 		    neat.o opti495.o opti895.o opti5x7.o scamp.o scat.o via_vt82c49x.o via_vt82c505.o \
-		    sis_85c310.o sis_85c4xx.o sis_85c496.o opti283.o opti291.o umc491.o \
+		    sis_85c310.o sis_85c4xx.o sis_85c496.o sis_85c50x.o opti283.o opti291.o umc491.o \
 		    via_apollo.o via_pipc.o wd76c10.o vl82c480.o
 
 MCHOBJ		:= machine.o machine_table.o \
diff --git a/src/win/win_ui.c b/src/win/win_ui.c
index 7d9c88164..0cc399117 100644
--- a/src/win/win_ui.c
+++ b/src/win/win_ui.c
@@ -70,8 +70,11 @@ extern WCHAR	wopenfilestring[512];
 
 /* Local data. */
 static wchar_t	wTitle[512];
+#ifndef NO_KEYBOARD_HOOK
 static HHOOK	hKeyboardHook;
-static int	hook_enabled = 0, manager_wm = 0;
+static int	hook_enabled = 0;
+#endif
+static int	manager_wm = 0;
 static int	save_window_pos = 0, pause_state = 0;
 static int  dpi = 96;
 static int  padded_frame = 0;
@@ -295,6 +298,7 @@ ResetAllMenus(void)
 }
 
 
+#ifndef NO_KEYBOARD_HOOK
 static LRESULT CALLBACK
 LowLevelKeyboardProc(int nCode, WPARAM wParam, LPARAM lParam)
 {
@@ -326,6 +330,7 @@ LowLevelKeyboardProc(int nCode, WPARAM wParam, LPARAM lParam)
 
     return(CallNextHookEx(hKeyboardHook, nCode, wParam, lParam));
 }
+#endif
 
 
 void
@@ -360,7 +365,9 @@ plat_power_off(void)
        run before the main thread is terminated */
     cycles -= 99999999;
 
+#ifndef NO_KEYBOARD_HOOK
     UnhookWindowsHookEx(hKeyboardHook);
+#endif
 
     KillTimer(hwndMain, TIMER_1SEC);
     PostQuitMessage(0);