diff --git a/src/video/vid_ati_mach64.c b/src/video/vid_ati_mach64.c
index a5325e8f7..7f4e2c7c9 100644
--- a/src/video/vid_ati_mach64.c
+++ b/src/video/vid_ati_mach64.c
@@ -3532,13 +3532,10 @@ static void *mach64_common_init(const device_t *info)
                    mach64_overlay_draw);
     mach64->svga.dac_hwcursor.cur_ysize = 64;
 
-        if (info->flags & DEVICE_PCI)
-                mem_mapping_disable(&mach64->bios_rom.mapping);
-
-			mem_mapping_add(&mach64->linear_mapping,        0,       0,       svga_read_linear, svga_readw_linear, svga_readl_linear, svga_write_linear, svga_writew_linear, svga_writel_linear, NULL, MEM_MAPPING_EXTERNAL, &mach64->svga);
-        	mem_mapping_add(&mach64->mmio_linear_mapping,   0,       0,       mach64_ext_readb, mach64_ext_readw,  mach64_ext_readl,  mach64_ext_writeb, mach64_ext_writew,  mach64_ext_writel,  NULL, MEM_MAPPING_EXTERNAL,  mach64);
-	        mem_mapping_add(&mach64->mmio_linear_mapping_2, 0,       0,       mach64_ext_readb, mach64_ext_readw,  mach64_ext_readl,  mach64_ext_writeb, mach64_ext_writew,  mach64_ext_writel,  NULL, MEM_MAPPING_EXTERNAL,  mach64);
-        	mem_mapping_add(&mach64->mmio_mapping,          0xbc000, 0x04000, mach64_ext_readb, mach64_ext_readw,  mach64_ext_readl,  mach64_ext_writeb, mach64_ext_writew,  mach64_ext_writel,  NULL, MEM_MAPPING_EXTERNAL,  mach64);
+	mem_mapping_add(&mach64->linear_mapping,        0,       0,       svga_read_linear, svga_readw_linear, svga_readl_linear, svga_write_linear, svga_writew_linear, svga_writel_linear, NULL, MEM_MAPPING_EXTERNAL, &mach64->svga);
+       	mem_mapping_add(&mach64->mmio_linear_mapping,   0,       0,       mach64_ext_readb, mach64_ext_readw,  mach64_ext_readl,  mach64_ext_writeb, mach64_ext_writew,  mach64_ext_writel,  NULL, MEM_MAPPING_EXTERNAL,  mach64);
+        mem_mapping_add(&mach64->mmio_linear_mapping_2, 0,       0,       mach64_ext_readb, mach64_ext_readw,  mach64_ext_readl,  mach64_ext_writeb, mach64_ext_writew,  mach64_ext_writel,  NULL, MEM_MAPPING_EXTERNAL,  mach64);
+       	mem_mapping_add(&mach64->mmio_mapping,          0xbc000, 0x04000, mach64_ext_readb, mach64_ext_readw,  mach64_ext_readl,  mach64_ext_writeb, mach64_ext_writew,  mach64_ext_writel,  NULL, MEM_MAPPING_EXTERNAL,  mach64);
         mem_mapping_disable(&mach64->mmio_mapping);
 
         mach64_io_set(mach64);
@@ -3604,6 +3601,9 @@ static void *mach64gx_init(const device_t *info)
 	else if (info->flags & DEVICE_ISA)
 	        rom_init(&mach64->bios_rom, BIOS_ISA_ROM_PATH, 0xc0000, 0x8000, 0x7fff, 0, MEM_MAPPING_EXTERNAL);
 
+        if (info->flags & DEVICE_PCI)
+                mem_mapping_disable(&mach64->bios_rom.mapping);
+
         return mach64;
 }
 static void *mach64vt2_init(const device_t *info)
@@ -3628,6 +3628,9 @@ static void *mach64vt2_init(const device_t *info)
 
         rom_init(&mach64->bios_rom, BIOS_ROMVT2_PATH, 0xc0000, 0x8000, 0x7fff, 0, MEM_MAPPING_EXTERNAL);
 
+        if (info->flags & DEVICE_PCI)
+                mem_mapping_disable(&mach64->bios_rom.mapping);
+
         svga->vblank_start = mach64_vblank_start;
 
         return mach64;
diff --git a/src/video/vid_cl54xx.c b/src/video/vid_cl54xx.c
index b4a7057f0..174dc5037 100644
--- a/src/video/vid_cl54xx.c
+++ b/src/video/vid_cl54xx.c
@@ -3708,6 +3708,11 @@ cl_pci_write(int func, int addr, uint8_t val, void *p)
 			io_sethandler(0x03c0, 0x0020, gd54xx_in, NULL, NULL, gd54xx_out, NULL, NULL, gd54xx);
 		if ((val & PCI_COMMAND_MEM) && (gd54xx->vgablt_base != 0x00000000) && (gd54xx->vgablt_base < 0xfff00000))
 			mem_mapping_set_addr(&gd54xx->vgablt_mapping, gd54xx->vgablt_base, 0x1000);
+		if ((gd54xx->pci_regs[PCI_REG_COMMAND] & PCI_COMMAND_MEM) && (gd54xx->pci_regs[0x30] & 0x01)) {
+			uint32_t addr = (gd54xx->pci_regs[0x32] << 16) | (gd54xx->pci_regs[0x33] << 24);
+			mem_mapping_set_addr(&gd54xx->bios_rom.mapping, addr, 0x8000);
+		} else
+			mem_mapping_disable(&gd54xx->bios_rom.mapping);
 		gd543x_recalc_mapping(gd54xx);
 		break;
 
@@ -3735,7 +3740,7 @@ cl_pci_write(int func, int addr, uint8_t val, void *p)
 
 	case 0x30: case 0x32: case 0x33:
 		gd54xx->pci_regs[addr] = val;
-		if (gd54xx->pci_regs[0x30] & 0x01) {
+		if ((gd54xx->pci_regs[PCI_REG_COMMAND] & PCI_COMMAND_MEM) && (gd54xx->pci_regs[0x30] & 0x01)) {
 			uint32_t addr = (gd54xx->pci_regs[0x32] << 16) | (gd54xx->pci_regs[0x33] << 24);
 			mem_mapping_set_addr(&gd54xx->bios_rom.mapping, addr, 0x8000);
 		} else
@@ -4061,8 +4066,10 @@ static void
     }
     io_sethandler(0x03c0, 0x0020, gd54xx_in, NULL, NULL, gd54xx_out, NULL, NULL, gd54xx);
 
-    if (gd54xx->pci && id >= CIRRUS_ID_CLGD5430)
+    if (gd54xx->pci && id >= CIRRUS_ID_CLGD5430) {
 	pci_add_card(PCI_ADD_VIDEO, cl_pci_read, cl_pci_write, gd54xx);
+	mem_mapping_disable(&gd54xx->bios_rom.mapping);
+    }
 
     mem_mapping_set_p(&svga->mapping, gd54xx);
     mem_mapping_disable(&gd54xx->mmio_mapping);
diff --git a/src/video/vid_tgui9440.c b/src/video/vid_tgui9440.c
index 603acccb9..a4fd83a0e 100644
--- a/src/video/vid_tgui9440.c
+++ b/src/video/vid_tgui9440.c
@@ -3079,8 +3079,11 @@ static void *tgui_init(const device_t *info)
 
 	tgui->has_bios = (bios_fn != NULL);
 
-	if (tgui->has_bios)
+	if (tgui->has_bios) {
 		rom_init(&tgui->bios_rom, (char *) bios_fn, 0xc0000, 0x8000, 0x7fff, 0, MEM_MAPPING_EXTERNAL);
+		if (tgui->pci)
+			mem_mapping_disable(&tgui->bios_rom.mapping);
+	}
 
 	if (tgui->pci)
 		video_inform(VIDEO_FLAG_TYPE_SPECIAL, &timing_tgui_pci);
@@ -3107,7 +3110,7 @@ static void *tgui_init(const device_t *info)
 
         if (tgui->pci && (tgui->type >= TGUI_9440)) {
 		if (tgui->has_bios)
-		tgui->card = pci_add_card(PCI_ADD_VIDEO, tgui_pci_read, tgui_pci_write, tgui);
+			tgui->card = pci_add_card(PCI_ADD_VIDEO, tgui_pci_read, tgui_pci_write, tgui);
 		else
 			tgui->card = pci_add_card(PCI_ADD_VIDEO | PCI_ADD_STRICT, tgui_pci_read, tgui_pci_write, tgui);
 	}