diff --git a/src/devices/machine/saturn.cpp b/src/devices/machine/saturn.cpp
index a5f2db9cd85..6472c4ab3c8 100644
--- a/src/devices/machine/saturn.cpp
+++ b/src/devices/machine/saturn.cpp
@@ -964,10 +964,10 @@ static const gfx_layout tiles16x16x8_layout =
 
 
 GFXDECODE_START( stv )
-	GFXDECODE_ENTRY( 0x0000, 0, tiles8x8x4_layout,   0x00, (0x80*(2+1))  )
-	GFXDECODE_ENTRY( 0x0000, 0, tiles16x16x4_layout, 0x00, (0x80*(2+1))  )
-	GFXDECODE_ENTRY( 0x0000, 0, tiles8x8x8_layout,   0x00, (0x08*(2+1))  )
-	GFXDECODE_ENTRY( 0x0000, 0, tiles16x16x8_layout, 0x00, (0x08*(2+1))  )
+	GFXDECODE_ENTRY( nullptr, 0, tiles8x8x4_layout,   0x00, (0x80*(2+1))  )
+	GFXDECODE_ENTRY( nullptr, 0, tiles16x16x4_layout, 0x00, (0x80*(2+1))  )
+	GFXDECODE_ENTRY( nullptr, 0, tiles8x8x8_layout,   0x00, (0x08*(2+1))  )
+	GFXDECODE_ENTRY( nullptr, 0, tiles16x16x8_layout, 0x00, (0x08*(2+1))  )
 GFXDECODE_END
 
 WRITE_LINE_MEMBER(saturn_state::scudsp_end_w)
diff --git a/src/mame/drivers/2mindril.cpp b/src/mame/drivers/2mindril.cpp
index d776562a0f9..24492ebd5f3 100644
--- a/src/mame/drivers/2mindril.cpp
+++ b/src/mame/drivers/2mindril.cpp
@@ -403,10 +403,10 @@ static const gfx_layout tile_layout =
 };
 
 static GFXDECODE_START( 2mindril )
-	GFXDECODE_ENTRY( 0x0000,   0x000000, charlayout,       0x0000, 0x0400>>4 ) /* Dynamically modified */
+	GFXDECODE_ENTRY( nullptr,   0x000000, charlayout,       0x0000, 0x0400>>4 ) /* Dynamically modified */
 	GFXDECODE_ENTRY( "gfx2", 0x000000, tile_layout,      0x0000, 0x2000>>4 ) /* Tiles area */
 	GFXDECODE_ENTRY( "gfx1", 0x000000, spriteram_layout, 0x1000, 0x1000>>4 ) /* Sprites area */
-	GFXDECODE_ENTRY( 0x0000,   0x000000, pivotlayout,      0x0000,  0x400>>4 ) /* Dynamically modified */
+	GFXDECODE_ENTRY( nullptr,   0x000000, pivotlayout,      0x0000,  0x400>>4 ) /* Dynamically modified */
 GFXDECODE_END
 
 
diff --git a/src/mame/drivers/ace.cpp b/src/mame/drivers/ace.cpp
index 6a01c56fe37..57d96585296 100644
--- a/src/mame/drivers/ace.cpp
+++ b/src/mame/drivers/ace.cpp
@@ -289,10 +289,10 @@ static const gfx_layout scorelayout =
 
 static GFXDECODE_START( ace )
 	GFXDECODE_ENTRY( "gfx1", 0, charlayout,  0, 2 )
-	GFXDECODE_ENTRY( 0x0000, 0x8000, charlayout0, 0, 2 ) /* the game dynamically modifies this */
-	GFXDECODE_ENTRY( 0x0000, 0x8000, charlayout1, 0, 2 ) /* the game dynamically modifies this */
-	GFXDECODE_ENTRY( 0x0000, 0x8000, charlayout2, 0, 2 ) /* the game dynamically modifies this */
-	GFXDECODE_ENTRY( 0x0000, 0x8000, scorelayout, 0, 2 ) /* the game dynamically modifies this */
+	GFXDECODE_ENTRY( nullptr, 0x8000, charlayout0, 0, 2 ) /* the game dynamically modifies this */
+	GFXDECODE_ENTRY( nullptr, 0x8000, charlayout1, 0, 2 ) /* the game dynamically modifies this */
+	GFXDECODE_ENTRY( nullptr, 0x8000, charlayout2, 0, 2 ) /* the game dynamically modifies this */
+	GFXDECODE_ENTRY( nullptr, 0x8000, scorelayout, 0, 2 ) /* the game dynamically modifies this */
 GFXDECODE_END
 
 void aceal_state::ace_postload()
diff --git a/src/mame/drivers/btime.cpp b/src/mame/drivers/btime.cpp
index 407914ec409..c8b701f5518 100644
--- a/src/mame/drivers/btime.cpp
+++ b/src/mame/drivers/btime.cpp
@@ -1142,8 +1142,8 @@ static GFXDECODE_START( zoar )
 GFXDECODE_END
 
 static GFXDECODE_START( disco )
-	GFXDECODE_ENTRY( 0x0000, 0, disco_tile8layout,  0, 4 ) /* char set #1 */
-	GFXDECODE_ENTRY( 0x0000, 0, disco_tile16layout, 0, 4 ) /* sprites */
+	GFXDECODE_ENTRY( nullptr, 0, disco_tile8layout,  0, 4 ) /* char set #1 */
+	GFXDECODE_ENTRY( nullptr, 0, disco_tile16layout, 0, 4 ) /* sprites */
 GFXDECODE_END
 
 /***************************************************************************
diff --git a/src/mame/drivers/buggychl.cpp b/src/mame/drivers/buggychl.cpp
index 9e1e30c4a2a..6892af92550 100644
--- a/src/mame/drivers/buggychl.cpp
+++ b/src/mame/drivers/buggychl.cpp
@@ -303,7 +303,7 @@ static const gfx_layout spritelayout =
 };
 
 static GFXDECODE_START( buggychl )
-	GFXDECODE_ENTRY( 0x0000,           0, charlayout,   0, 8 ) /* decoded at runtime */
+	GFXDECODE_ENTRY( nullptr,           0, charlayout,   0, 8 ) /* decoded at runtime */
 	/* sprites are drawn pixel by pixel by draw_sprites() */
 	GFXDECODE_ENTRY( "gfx1", 0, spritelayout, 0, 8 )
 GFXDECODE_END
diff --git a/src/mame/drivers/cvs.cpp b/src/mame/drivers/cvs.cpp
index a6a64297e91..4c013254dfa 100644
--- a/src/mame/drivers/cvs.cpp
+++ b/src/mame/drivers/cvs.cpp
@@ -924,7 +924,7 @@ static const gfx_layout charlayout =
 
 static GFXDECODE_START( cvs )
 	GFXDECODE_ENTRY( "gfx1", 0x0000, charlayout, 0, 256+4 )
-	GFXDECODE_ENTRY( 0x0000,   0x0000, charlayout, 0, 256+4 )
+	GFXDECODE_ENTRY( nullptr,   0x0000, charlayout, 0, 256+4 )
 GFXDECODE_END
 
 
diff --git a/src/mame/drivers/decocass.cpp b/src/mame/drivers/decocass.cpp
index 518c404cd4f..31f18fc6083 100644
--- a/src/mame/drivers/decocass.cpp
+++ b/src/mame/drivers/decocass.cpp
@@ -680,10 +680,10 @@ static const gfx_layout objlayout =
 };
 
 static GFXDECODE_START( decocass )
-	GFXDECODE_ENTRY( 0x0000, 0x6000, charlayout,       0, 4 )  /* char set #1 */
-	GFXDECODE_ENTRY( 0x0000, 0x6000, spritelayout,     0, 4 )  /* sprites */
-	GFXDECODE_ENTRY( 0x0000, 0xd000, tilelayout,      32, 2 )  /* background tiles */
-	GFXDECODE_ENTRY( 0x0000, 0xd800, objlayout,       48, 4 )  /* object */
+	GFXDECODE_ENTRY( nullptr, 0x6000, charlayout,       0, 4 )  /* char set #1 */
+	GFXDECODE_ENTRY( nullptr, 0x6000, spritelayout,     0, 4 )  /* sprites */
+	GFXDECODE_ENTRY( nullptr, 0xd000, tilelayout,      32, 2 )  /* background tiles */
+	GFXDECODE_ENTRY( nullptr, 0xd800, objlayout,       48, 4 )  /* object */
 GFXDECODE_END
 
 PALETTE_INIT_MEMBER(decocass_state, decocass)
diff --git a/src/mame/drivers/fastfred.cpp b/src/mame/drivers/fastfred.cpp
index db6b048530c..21e01328518 100644
--- a/src/mame/drivers/fastfred.cpp
+++ b/src/mame/drivers/fastfred.cpp
@@ -626,7 +626,7 @@ GFXDECODE_END
 
 static GFXDECODE_START( imago )
 	GFXDECODE_ENTRY( "gfx1", 0,      charlayout,          0, 32 )
-	GFXDECODE_ENTRY( 0x0000,   0xb800, imago_spritelayout,  0, 32 )
+	GFXDECODE_ENTRY( nullptr,   0xb800, imago_spritelayout,  0, 32 )
 	GFXDECODE_ENTRY( "gfx3", 0,      charlayout,          0, 32 )
 	GFXDECODE_ENTRY( "gfx4", 0,      imago_char_1bpp, 0x140,  1 )
 GFXDECODE_END
diff --git a/src/mame/drivers/gottlieb.cpp b/src/mame/drivers/gottlieb.cpp
index b934fc3739b..d9913f744d8 100644
--- a/src/mame/drivers/gottlieb.cpp
+++ b/src/mame/drivers/gottlieb.cpp
@@ -1747,7 +1747,7 @@ static const gfx_layout fg_layout =
 };
 
 static GFXDECODE_START( gfxdecode )
-	GFXDECODE_ENTRY( 0x0000,      0x4000, bg_ram_layout, 0, 1 )   /* the game dynamically modifies this */
+	GFXDECODE_ENTRY( nullptr,      0x4000, bg_ram_layout, 0, 1 )   /* the game dynamically modifies this */
 	GFXDECODE_ENTRY( "bgtiles", 0x0000, bg_rom_layout, 0, 1 )
 	GFXDECODE_ENTRY( "sprites", 0x0000, fg_layout,     0, 1 )
 GFXDECODE_END
diff --git a/src/mame/drivers/lemmings.cpp b/src/mame/drivers/lemmings.cpp
index b329a4ed778..5af69bba418 100644
--- a/src/mame/drivers/lemmings.cpp
+++ b/src/mame/drivers/lemmings.cpp
@@ -220,7 +220,7 @@ static const gfx_layout sprite_layout =
 static GFXDECODE_START( lemmings )
 	GFXDECODE_ENTRY( "gfx1", 0, sprite_layout,  0, 16 ) /* Sprites 16x16 */
 	GFXDECODE_ENTRY( "gfx2", 0, sprite_layout,  0, 16 ) /* Sprites 16x16 */
-	GFXDECODE_ENTRY( 0x0000,           0, charlayout,         0, 16 ) /* Dynamically modified */
+	GFXDECODE_ENTRY( nullptr,           0, charlayout,         0, 16 ) /* Dynamically modified */
 GFXDECODE_END
 
 /******************************************************************************/
diff --git a/src/mame/drivers/mogura.cpp b/src/mame/drivers/mogura.cpp
index a7e23f525c5..9310a5aee94 100644
--- a/src/mame/drivers/mogura.cpp
+++ b/src/mame/drivers/mogura.cpp
@@ -190,7 +190,7 @@ static const gfx_layout tiles8x8_layout =
 };
 
 static GFXDECODE_START( mogura )
-	GFXDECODE_ENTRY( 0x0000, 0, tiles8x8_layout, 0, 8 )
+	GFXDECODE_ENTRY( nullptr, 0, tiles8x8_layout, 0, 8 )
 GFXDECODE_END
 
 void mogura_state::machine_start()
diff --git a/src/mame/drivers/namcos22.cpp b/src/mame/drivers/namcos22.cpp
index 7440f5e57f0..64000211811 100644
--- a/src/mame/drivers/namcos22.cpp
+++ b/src/mame/drivers/namcos22.cpp
@@ -3712,12 +3712,12 @@ static const gfx_layout namcos22_cg_layout =
 #undef XOR
 
 static GFXDECODE_START( namcos22 )
-	GFXDECODE_ENTRY( 0x0000,      0, namcos22_cg_layout,   0, 0x800 )
+	GFXDECODE_ENTRY( nullptr,      0, namcos22_cg_layout,   0, 0x800 )
 	GFXDECODE_ENTRY( "textile", 0, texture_tile_layout,  0, 0x80 )
 GFXDECODE_END
 
 static GFXDECODE_START( super )
-	GFXDECODE_ENTRY( 0x0000,      0, namcos22_cg_layout,   0, 0x800 )
+	GFXDECODE_ENTRY( nullptr,      0, namcos22_cg_layout,   0, 0x800 )
 	GFXDECODE_ENTRY( "textile", 0, texture_tile_layout,  0, 0x80 )
 	GFXDECODE_ENTRY( "sprite",  0, sprite_layout,        0, 0x80 )
 GFXDECODE_END
diff --git a/src/mame/drivers/namcos23.cpp b/src/mame/drivers/namcos23.cpp
index 5f178d255fa..66106e4bafd 100644
--- a/src/mame/drivers/namcos23.cpp
+++ b/src/mame/drivers/namcos23.cpp
@@ -3523,7 +3523,7 @@ static const gfx_layout namcos23_cg_layout =
 }; /* cg_layout */
 
 static GFXDECODE_START( namcos23 )
-	GFXDECODE_ENTRY( 0x0000, 0, namcos23_cg_layout, 0, 0x800 )
+	GFXDECODE_ENTRY( nullptr, 0, namcos23_cg_layout, 0, 0x800 )
 GFXDECODE_END
 
 
diff --git a/src/mame/drivers/polyplay.cpp b/src/mame/drivers/polyplay.cpp
index e7361684c3b..f714f28dc77 100644
--- a/src/mame/drivers/polyplay.cpp
+++ b/src/mame/drivers/polyplay.cpp
@@ -250,7 +250,7 @@ static const gfx_layout charlayout_3_bit =
 
 static GFXDECODE_START( polyplay )
 	GFXDECODE_ENTRY( "gfx1", 0x0000, charlayout_1_bit, 0, 1 )
-	GFXDECODE_ENTRY( 0x0000,   0xec00, charlayout_3_bit, 2, 1 )
+	GFXDECODE_ENTRY( nullptr,   0xec00, charlayout_3_bit, 2, 1 )
 GFXDECODE_END
 
 
diff --git a/src/mame/drivers/segag80r.cpp b/src/mame/drivers/segag80r.cpp
index 34abd8086a1..6eb4edb91f3 100644
--- a/src/mame/drivers/segag80r.cpp
+++ b/src/mame/drivers/segag80r.cpp
@@ -785,18 +785,18 @@ static const gfx_layout charlayout =
 
 
 static GFXDECODE_START( segag80r )
-	GFXDECODE_ENTRY( 0x0000, 0x0000, charlayout, 0, 16 )
+	GFXDECODE_ENTRY( nullptr, 0x0000, charlayout, 0, 16 )
 GFXDECODE_END
 
 
 static GFXDECODE_START( spaceod )
-	GFXDECODE_ENTRY( 0x0000,           0x0000, charlayout,        0, 16 )
+	GFXDECODE_ENTRY( nullptr,           0x0000, charlayout,        0, 16 )
 	GFXDECODE_ENTRY( "gfx1", 0x0000, gfx_8x8x6_planar, 64, 1 )
 GFXDECODE_END
 
 
 static GFXDECODE_START( monsterb )
-	GFXDECODE_ENTRY( 0x0000,           0x0000, charlayout,        0, 16 )
+	GFXDECODE_ENTRY( nullptr,           0x0000, charlayout,        0, 16 )
 	GFXDECODE_ENTRY( "gfx1", 0x0000, gfx_8x8x2_planar, 64, 16 )
 GFXDECODE_END
 
diff --git a/src/mame/drivers/snk6502.cpp b/src/mame/drivers/snk6502.cpp
index d0a8f95abe8..4631b0fff65 100644
--- a/src/mame/drivers/snk6502.cpp
+++ b/src/mame/drivers/snk6502.cpp
@@ -725,17 +725,17 @@ static const gfx_layout charlayout_memory =
 
 
 static GFXDECODE_START( sasuke )
-	GFXDECODE_ENTRY( 0x0000,           0x1000, swapcharlayout,      0, 4 )    /* the game dynamically modifies this */
+	GFXDECODE_ENTRY( nullptr,           0x1000, swapcharlayout,      0, 4 )    /* the game dynamically modifies this */
 	GFXDECODE_ENTRY( "gfx1", 0x0000, swapcharlayout,    4*4, 4 )
 GFXDECODE_END
 
 static GFXDECODE_START( satansat )
-	GFXDECODE_ENTRY( 0x0000,           0x1000, charlayout_memory,   0, 4 )    /* the game dynamically modifies this */
+	GFXDECODE_ENTRY( nullptr,           0x1000, charlayout_memory,   0, 4 )    /* the game dynamically modifies this */
 	GFXDECODE_ENTRY( "gfx1", 0x0000, charlayout,        4*4, 4 )
 GFXDECODE_END
 
 static GFXDECODE_START( vanguard )
-	GFXDECODE_ENTRY( 0x0000,           0x1000, charlayout_memory,   0, 8 )    /* the game dynamically modifies this */
+	GFXDECODE_ENTRY( nullptr,           0x1000, charlayout_memory,   0, 8 )    /* the game dynamically modifies this */
 	GFXDECODE_ENTRY( "gfx1", 0x0000, charlayout,        8*4, 8 )
 GFXDECODE_END
 
diff --git a/src/mame/drivers/ssv.cpp b/src/mame/drivers/ssv.cpp
index 44c758258a0..14bd978b709 100644
--- a/src/mame/drivers/ssv.cpp
+++ b/src/mame/drivers/ssv.cpp
@@ -2444,8 +2444,8 @@ static const gfx_layout layout_16x8x6_ram =
 };
 
 static GFXDECODE_START( eaglshot )
-	GFXDECODE_ENTRY( 0x0000, 0, layout_16x8x8_ram, 0, 0x8000/64 ) // [0] Sprites (256 colors, decoded from ram)
-	GFXDECODE_ENTRY( 0x0000, 0, layout_16x8x6_ram, 0, 0x8000/64 ) // [1] Sprites (64 colors, decoded from ram)
+	GFXDECODE_ENTRY( nullptr, 0, layout_16x8x8_ram, 0, 0x8000/64 ) // [0] Sprites (256 colors, decoded from ram)
+	GFXDECODE_ENTRY( nullptr, 0, layout_16x8x6_ram, 0, 0x8000/64 ) // [1] Sprites (64 colors, decoded from ram)
 GFXDECODE_END
 
 static const gfx_layout layout_16x16x8 =
diff --git a/src/mame/drivers/taito_f3.cpp b/src/mame/drivers/taito_f3.cpp
index 64a5ee07769..e76e72de430 100644
--- a/src/mame/drivers/taito_f3.cpp
+++ b/src/mame/drivers/taito_f3.cpp
@@ -386,10 +386,10 @@ static const gfx_layout tile_layout =
 };
 
 static GFXDECODE_START( taito_f3 )
-	GFXDECODE_ENTRY( 0x0000,   0x000000, charlayout,       0x0000, 0x0400>>4 ) /* Dynamically modified */
+	GFXDECODE_ENTRY( nullptr,   0x000000, charlayout,       0x0000, 0x0400>>4 ) /* Dynamically modified */
 	GFXDECODE_ENTRY( "gfx2", 0x000000, tile_layout,      0x0000, 0x2000>>4 ) /* Tiles area */
 	GFXDECODE_ENTRY( "gfx1", 0x000000, spriteram_layout, 0x1000, 0x1000>>4 ) /* Sprites area */
-	GFXDECODE_ENTRY( 0x0000,   0x000000, pivotlayout,      0x0000,  0x400>>4 ) /* Dynamically modified */
+	GFXDECODE_ENTRY( nullptr,   0x000000, pivotlayout,      0x0000,  0x400>>4 ) /* Dynamically modified */
 GFXDECODE_END
 
 /******************************************************************************/
@@ -523,10 +523,10 @@ static const gfx_layout bubsympb_tile_layout =
 
 
 static GFXDECODE_START( bubsympb )
-	GFXDECODE_ENTRY( 0x0000,           0x000000, charlayout,          0,  64 ) /* Dynamically modified */
+	GFXDECODE_ENTRY( nullptr,           0x000000, charlayout,          0,  64 ) /* Dynamically modified */
 	GFXDECODE_ENTRY( "gfx2", 0x000000, bubsympb_tile_layout, 0, 512 ) /* Tiles area */
 	GFXDECODE_ENTRY( "gfx1", 0x000000, bubsympb_sprite_layout, 4096, 256 ) /* Sprites area */
-	GFXDECODE_ENTRY( 0x0000,           0x000000, pivotlayout,         0,  64 ) /* Dynamically modified */
+	GFXDECODE_ENTRY( nullptr,           0x000000, pivotlayout,         0,  64 ) /* Dynamically modified */
 GFXDECODE_END
 
 static MACHINE_CONFIG_START( bubsympb, taito_f3_state )
diff --git a/src/mame/drivers/taito_l.cpp b/src/mame/drivers/taito_l.cpp
index a7aec64a26b..41e57d48498 100644
--- a/src/mame/drivers/taito_l.cpp
+++ b/src/mame/drivers/taito_l.cpp
@@ -1700,7 +1700,7 @@ static const gfx_layout char_layout =
 static GFXDECODE_START( taito_l )
 	GFXDECODE_ENTRY( "gfx1", 0, bg2_layout, 0, 16 )
 	GFXDECODE_ENTRY( "gfx1", 0, sp2_layout, 0, 16 )
-	GFXDECODE_ENTRY( 0x0000,           0, char_layout,  0, 16 )  // Ram-based
+	GFXDECODE_ENTRY( nullptr,           0, char_layout,  0, 16 )  // Ram-based
 GFXDECODE_END
 
 
diff --git a/src/mame/drivers/taitosj.cpp b/src/mame/drivers/taitosj.cpp
index 21018435e06..2d6460b2afc 100644
--- a/src/mame/drivers/taitosj.cpp
+++ b/src/mame/drivers/taitosj.cpp
@@ -1703,10 +1703,10 @@ static const gfx_layout spritelayout =
 
 
 static GFXDECODE_START( taitosj )
-	GFXDECODE_ENTRY( 0x0000, 0x9000, charlayout,   0, 8 )    /* the game dynamically modifies this */
-	GFXDECODE_ENTRY( 0x0000, 0x9000, spritelayout, 0, 8 )    /* the game dynamically modifies this */
-	GFXDECODE_ENTRY( 0x0000, 0xa800, charlayout,   0, 8 )    /* the game dynamically modifies this */
-	GFXDECODE_ENTRY( 0x0000, 0xa800, spritelayout, 0, 8 )    /* the game dynamically modifies this */
+	GFXDECODE_ENTRY( nullptr, 0x9000, charlayout,   0, 8 )    /* the game dynamically modifies this */
+	GFXDECODE_ENTRY( nullptr, 0x9000, spritelayout, 0, 8 )    /* the game dynamically modifies this */
+	GFXDECODE_ENTRY( nullptr, 0xa800, charlayout,   0, 8 )    /* the game dynamically modifies this */
+	GFXDECODE_ENTRY( nullptr, 0xa800, spritelayout, 0, 8 )    /* the game dynamically modifies this */
 GFXDECODE_END
 
 
diff --git a/src/mame/drivers/tatsumi.cpp b/src/mame/drivers/tatsumi.cpp
index 2b5eeef6f87..6d3056d6e77 100644
--- a/src/mame/drivers/tatsumi.cpp
+++ b/src/mame/drivers/tatsumi.cpp
@@ -832,7 +832,7 @@ GFXDECODE_END
 
 static GFXDECODE_START( roundup5 )
 	GFXDECODE_ENTRY( "gfx1", 0, spritelayout, 1024, 256)
-	GFXDECODE_ENTRY( 0x0000, 0, roundup5_vramlayout, 0, 16)
+	GFXDECODE_ENTRY( nullptr, 0, roundup5_vramlayout, 0, 16)
 GFXDECODE_END
 
 static GFXDECODE_START( cyclwarr )
diff --git a/src/mame/drivers/tiamc1.cpp b/src/mame/drivers/tiamc1.cpp
index 1a87c826702..ac9d19a3df8 100644
--- a/src/mame/drivers/tiamc1.cpp
+++ b/src/mame/drivers/tiamc1.cpp
@@ -216,7 +216,7 @@ static const gfx_layout char_layout =
 };
 
 static GFXDECODE_START( tiamc1 )
-	GFXDECODE_ENTRY( 0x0000, 0x0000, char_layout, 0, 16 )
+	GFXDECODE_ENTRY( nullptr, 0x0000, char_layout, 0, 16 )
 	GFXDECODE_ENTRY( "gfx1", 0x0000, sprites16x16_layout, 0, 16 )
 GFXDECODE_END
 
diff --git a/src/mame/drivers/toaplan2.cpp b/src/mame/drivers/toaplan2.cpp
index 2d3435834da..e12b8796e75 100644
--- a/src/mame/drivers/toaplan2.cpp
+++ b/src/mame/drivers/toaplan2.cpp
@@ -3057,7 +3057,7 @@ static const gfx_layout fixeightblayout =
 };
 
 static GFXDECODE_START( truxton2 )
-	GFXDECODE_ENTRY( 0x0000,   0, truxton2_tx_tilelayout, 64*16, 64 )
+	GFXDECODE_ENTRY( nullptr,   0, truxton2_tx_tilelayout, 64*16, 64 )
 GFXDECODE_END
 
 static GFXDECODE_START( raizing )
@@ -3065,7 +3065,7 @@ static GFXDECODE_START( raizing )
 GFXDECODE_END
 
 static GFXDECODE_START( batrider )
-	GFXDECODE_ENTRY( 0x0000,   0, batrider_tx_tilelayout, 64*16, 64 )
+	GFXDECODE_ENTRY( nullptr,   0, batrider_tx_tilelayout, 64*16, 64 )
 GFXDECODE_END
 
 static GFXDECODE_START( fixeightbl )
diff --git a/src/mame/drivers/trvmadns.cpp b/src/mame/drivers/trvmadns.cpp
index a1c9c431b51..aabba09848a 100644
--- a/src/mame/drivers/trvmadns.cpp
+++ b/src/mame/drivers/trvmadns.cpp
@@ -294,7 +294,7 @@ static const gfx_layout charlayout =
 };
 
 static GFXDECODE_START( trvmadns )
-	GFXDECODE_ENTRY( 0x0000, 0x6000, charlayout, 0, 4 ) // doesn't matter where we point this, all the tiles are decoded while the game runs
+	GFXDECODE_ENTRY( nullptr, 0x6000, charlayout, 0, 4 ) // doesn't matter where we point this, all the tiles are decoded while the game runs
 GFXDECODE_END
 
 TILE_GET_INFO_MEMBER(trvmadns_state::get_bg_tile_info)
diff --git a/src/mame/drivers/tryout.cpp b/src/mame/drivers/tryout.cpp
index cb82c764133..aa1769db1a7 100644
--- a/src/mame/drivers/tryout.cpp
+++ b/src/mame/drivers/tryout.cpp
@@ -185,7 +185,7 @@ static const gfx_layout spritelayout =
 static GFXDECODE_START( tryout )
 	GFXDECODE_ENTRY( "gfx1", 0, charlayout,   0, 8 )
 	GFXDECODE_ENTRY( "gfx2", 0, spritelayout, 0, 4 )
-	GFXDECODE_ENTRY( 0x0000,   0, vramlayout,   0, 4 )
+	GFXDECODE_ENTRY( nullptr,   0, vramlayout,   0, 4 )
 GFXDECODE_END
 
 static MACHINE_CONFIG_START( tryout, tryout_state )
diff --git a/src/mame/drivers/usgames.cpp b/src/mame/drivers/usgames.cpp
index 36bbff55732..892dfbc9649 100644
--- a/src/mame/drivers/usgames.cpp
+++ b/src/mame/drivers/usgames.cpp
@@ -209,7 +209,7 @@ static const gfx_layout charlayout =
 };
 
 static GFXDECODE_START( usgames )
-	GFXDECODE_ENTRY( 0x0000, 0x2800, charlayout, 0, 256 )
+	GFXDECODE_ENTRY( nullptr, 0x2800, charlayout, 0, 256 )
 GFXDECODE_END
 
 
diff --git a/src/mame/video/madalien.cpp b/src/mame/video/madalien.cpp
index 926d81cade5..cd9447a6478 100644
--- a/src/mame/video/madalien.cpp
+++ b/src/mame/video/madalien.cpp
@@ -361,7 +361,7 @@ static const gfx_layout tilelayout =
 
 
 static GFXDECODE_START( madalien )
-	GFXDECODE_ENTRY( 0x0000,   0, charlayout,     0x20, 2 ) /* foreground characters, stored in RAM */
+	GFXDECODE_ENTRY( nullptr,   0, charlayout,     0x20, 2 ) /* foreground characters, stored in RAM */
 	GFXDECODE_ENTRY( "gfx1", 0, tilelayout,        0, 4 )
 	GFXDECODE_ENTRY( "gfx2", 0, headlightlayout,   0, 1 )
 GFXDECODE_END