diff --git a/src/mame/drivers/meritm.c b/src/mame/drivers/meritm.c
index a3236663645..d210f33f467 100644
--- a/src/mame/drivers/meritm.c
+++ b/src/mame/drivers/meritm.c
@@ -1889,6 +1889,17 @@ static DRIVER_INIT(megat4)
 	ds1204_init(machine, 0, megat4_ds1204_nvram);
 }
 
+static DRIVER_INIT(megat4c) /* First version of MegaTouch IV requires "key" like previous MegaTouch versions */
+{
+	static const UINT8 megat4c_ds1204_key[8] =
+		{ 0xf0, 0xaa, 0x0f, 0x0f, 0x55, 0x55, 0xff, 0xab };
+
+	static const UINT8 megat4_ds1204_nvram[16] =
+		{ 0xe3, 0x08, 0x39, 0xd8, 0x4c, 0xbb, 0xc4, 0xf8, 0xf0, 0xe2, 0xd8, 0x77, 0xa8, 0x3d, 0x95, 0x02 };
+
+	ds1204_init(machine, megat4c_ds1204_key, megat4_ds1204_nvram);
+}
+
 static DRIVER_INIT(megat4te)
 {
 	static const UINT8 megat4te_ds1204_nvram[16] =
@@ -1968,7 +1979,7 @@ GAME( 1996, megat3te,  megat3, meritm_crt260, meritm_crt260, megat3te, ROT0, "Me
 GAME( 1996, megat4,    0,      meritm_crt260, meritm_crt260, megat4,   ROT0, "Merit", "Megatouch IV (9255-40-01 ROE, Standard version)", GAME_IMPERFECT_GRAPHICS )
 GAME( 1996, megat4a,   megat4, meritm_crt260, meritm_crt260, megat4,   ROT0, "Merit", "Megatouch IV (9255-40-01 ROD, Standard version)", GAME_IMPERFECT_GRAPHICS )
 GAME( 1996, megat4b,   megat4, meritm_crt260, meritm_crt260, megat4,   ROT0, "Merit", "Megatouch IV (9255-40-01 ROB, Standard version)", GAME_IMPERFECT_GRAPHICS )
-GAME( 1996, megat4c,   megat4, meritm_crt260, meritm_crt260, megat4,   ROT0, "Merit", "Megatouch IV (9255-40-01 RO, Standard version)", GAME_IMPERFECT_GRAPHICS )
+GAME( 1996, megat4c,   megat4, meritm_crt260, meritm_crt260, megat4c,  ROT0, "Merit", "Megatouch IV (9255-40-01 RO, Standard version)", GAME_IMPERFECT_GRAPHICS )
 GAME( 1996, megat4s,   megat4, meritm_crt260, meritm_crt260, megat4,   ROT0, "Merit", "Super Megatouch IV (9255-41-01 ROG, Standard version)", GAME_IMPERFECT_GRAPHICS )
 GAME( 1996, megat4sn,  megat4, meritm_crt260, meritm_crt260, megat4,   ROT0, "Merit", "Super Megatouch IV (9255-41-07 ROG, New Jersey version)", GAME_IMPERFECT_GRAPHICS )
 GAME( 1996, megat4te,  megat4, meritm_crt260, meritm_crt260, megat4te, ROT0, "Merit", "Megatouch IV Tournament Edition (9255-50-01 ROD, Standard version)", GAME_IMPERFECT_GRAPHICS )