diff --git a/src/mame/drivers/system1.cpp b/src/mame/drivers/system1.cpp
index 4954002a392..7b7ad4dc59c 100644
--- a/src/mame/drivers/system1.cpp
+++ b/src/mame/drivers/system1.cpp
@@ -5376,37 +5376,11 @@ DRIVER_INIT_MEMBER(system1_state,sega315_5132)
 	sega_decode(m_maincpu_region->base(), m_decrypted_opcodes, 0x8000, convtable);
 }
 
-// todo, collapse with above (this is sega315_5132 with an extra layer, probably bootleg)
 DRIVER_INIT_MEMBER(system1_state,myherok)
 {
-	static const UINT8 convtable[32][4] =
-	{
-		/*       opcode                   data                     address      */
-		/*  A    B    C    D         A    B    C    D                           */
-		{ 0x20,0x00,0xa0,0x80 }, { 0x80,0xa0,0x88,0xa8 },   /* ...0...0...0...0 */
-		{ 0x20,0x00,0xa0,0x80 }, { 0x80,0xa0,0x88,0xa8 },   /* ...0...0...0...1 */
-		{ 0xa8,0xa0,0x88,0x80 }, { 0xa8,0xa0,0x88,0x80 },   /* ...0...0...1...0 */
-		{ 0x08,0x88,0x00,0x80 }, { 0x80,0xa0,0x88,0xa8 },   /* ...0...0...1...1 */
-		{ 0x20,0x00,0xa0,0x80 }, { 0x28,0xa8,0x08,0x88 },   /* ...0...1...0...0 */
-		{ 0x20,0x00,0xa0,0x80 }, { 0x08,0x88,0x00,0x80 },   /* ...0...1...0...1 */
-		{ 0x28,0xa8,0x08,0x88 }, { 0xa8,0xa0,0x88,0x80 },   /* ...0...1...1...0 */
-		{ 0x08,0x88,0x00,0x80 }, { 0xa8,0xa0,0x88,0x80 },   /* ...0...1...1...1 */
-		{ 0x28,0xa8,0x08,0x88 }, { 0x20,0x00,0xa0,0x80 },   /* ...1...0...0...0 */
-		{ 0x80,0xa0,0x88,0xa8 }, { 0x20,0x00,0xa0,0x80 },   /* ...1...0...0...1 */
-		{ 0x80,0xa0,0x88,0xa8 }, { 0x80,0xa0,0x88,0xa8 },   /* ...1...0...1...0 */
-		{ 0xa8,0xa0,0x88,0x80 }, { 0x80,0xa0,0x88,0xa8 },   /* ...1...0...1...1 */
-		{ 0x88,0x80,0x08,0x00 }, { 0x88,0x80,0x08,0x00 },   /* ...1...1...0...0 */
-		{ 0x88,0x80,0x08,0x00 }, { 0x08,0x88,0x00,0x80 },   /* ...1...1...0...1 */
-		{ 0x88,0x80,0x08,0x00 }, { 0xa8,0xa0,0x88,0x80 },   /* ...1...1...1...0 */
-		{ 0x88,0x80,0x08,0x00 }, { 0xa8,0xa0,0x88,0x80 }    /* ...1...1...1...1 */
-	};
-
-
 	int A;
 	UINT8 *rom;
 
-	DRIVER_INIT_CALL(bank00);
-
 	/* additionally to the usual protection, all the program ROMs have data lines */
 	/* D0 and D1 swapped. */
 	rom = m_maincpu_region->base();
@@ -5443,7 +5417,7 @@ DRIVER_INIT_MEMBER(system1_state,myherok)
 		}
 	}
 
-	sega_decode(m_maincpu_region->base(), m_decrypted_opcodes, 0x8000, convtable);
+	DRIVER_INIT_CALL(sega315_5132);
 }
 
 DRIVER_INIT_MEMBER(system1_state,sega315_5162)
@@ -5536,62 +5510,10 @@ DRIVER_INIT_MEMBER(system1_state,sega315_5177)
 	sega_decode_2(m_maincpu_region->base(), m_decrypted_opcodes, xor_table, swap_table);
 }
 
-// todo, refactor into above
 DRIVER_INIT_MEMBER(system1_state,sega315_5177_s2)
 {
-	// 315-5177
-	static const UINT8 xor_table[128] =
-	{
-		0x04,0x54,0x51,0x15,0x40,0x44,0x01,0x51,0x55,0x10,0x44,0x41,
-		0x05,0x55,0x50,0x14,0x41,0x45,0x00,0x50,0x54,0x11,0x45,0x40,
-		0x04,0x54,0x51,0x15,0x40,0x44,0x01,0x51,0x55,0x10,0x44,0x41,
-		0x05,0x55,0x50,0x14,0x41,0x45,0x00,0x50,0x54,0x11,0x45,0x40,
-		0x04,0x54,0x51,0x15,0x40,0x44,0x01,0x51,0x55,0x10,0x44,0x41,
-		0x05,0x55,0x50,0x14,
-
-		0x04,0x54,0x51,0x15,0x40,0x44,0x01,0x51,0x55,0x10,0x44,0x41,
-		0x05,0x55,0x50,0x14,0x41,0x45,0x00,0x50,0x54,0x11,0x45,0x40,
-		0x04,0x54,0x51,0x15,0x40,0x44,0x01,0x51,0x55,0x10,0x44,0x41,
-		0x05,0x55,0x50,0x14,0x41,0x45,0x00,0x50,0x54,0x11,0x45,0x40,
-		0x04,0x54,0x51,0x15,0x40,0x44,0x01,0x51,0x55,0x10,0x44,0x41,
-		0x05,0x55,0x50,0x14,
-	};
-
-	static const int swap_table[128] =
-	{
-		0,0,0,0,
-		1,1,1,1,1,
-		2,2,2,2,2,
-		3,3,3,3,
-		4,4,4,4,4,
-		5,5,5,5,5,
-		6,6,6,6,6,
-		7,7,7,7,7,
-		8,8,8,8,
-		9,9,9,9,9,
-		10,10,10,10,10,
-		11,11,11,11,11,
-		12,12,12,12,12,
-		13,13,
-
-		8,8,8,8,
-		9,9,9,9,9,
-		10,10,10,10,10,
-		11,11,11,11,
-		12,12,12,12,12,
-		13,13,13,13,13,
-		14,14,14,14,14,
-		15,15,15,15,15,
-		16,16,16,16,
-		17,17,17,17,17,
-		18,18,18,18,18,
-		19,19,19,19,19,
-		20,20,20,20,20,
-		21,21,
-	};
-
+	DRIVER_INIT_CALL(sega315_5177);
 	DRIVER_INIT_CALL(bank0c);
-	sega_decode_2(m_maincpu_region->base(), m_decrypted_opcodes, xor_table, swap_table);
 }