diff --git a/src/mame/drivers/neodrvr.c b/src/mame/drivers/neodrvr.c
index 70fac802585..44e20a1d877 100644
--- a/src/mame/drivers/neodrvr.c
+++ b/src/mame/drivers/neodrvr.c
@@ -5672,13 +5672,10 @@ ROM_START( ms5pcb ) /* Encrypted Set */
 	/* this contains both an ASIA and JAPAN bios, HARDDIP3 on the PCB selects which to use */
 	ROM_LOAD16_WORD_SWAP( "268-bios.bin", 0x00000, 0x80000, CRC(b4590283) SHA1(47047ed5b6062babc0a0bebcc30e4b3f021e115a) )
 
-	ROM_REGION( 0x50000, "audio", 0 )
-	/* Encrypted, we load it here for reference and replace with decrypted ROM */
+	/* Encrypted (slightly different encryption on this single board PCB) */
+	ROM_REGION( 0x80000, "audiocrypt", 0 )
 	ROM_LOAD( "268-m1.bin", 0x00000, 0x10000, CRC(58b107d0) SHA1(cc7fe66ff4f9c026cde4df06f86c848eb21f7af8) )
-	/* Decrypted */
-	ROM_LOAD( "268-m1_decrypted.bin", 0x00000, 0x10000, CRC(3c0655a7) SHA1(ae839d4c2b87a7aa3dd8e5caddc43eb75ee9b732) ) /* not a 100% match for encrypted version */
-	ROM_RELOAD( 0x10000, 0x10000 )
-
+	ROM_REGION( 0x90000, "audio", ROMREGION_ERASEFF )
 
 	ROM_Y_ZOOM
 
@@ -7039,7 +7036,7 @@ static DRIVER_INIT( ms5pcb )
 	mslug5_decrypt_68k(machine);
 	svcpcb_gfx_decrypt(machine);
 	kof2000_neogeo_gfx_decrypt(machine, 0x19);
-	//neogeo_cmc50_m1_decrypt(machine, 0x1543); // wrong, or there is some extra address swap first
+	neogeo_ms5pcb_m1_decrypt(machine);
 
 	neogeo_fixed_layer_bank_type = 2;
 	svcpcb_s1data_decrypt(machine);
diff --git a/src/mame/includes/neogeo.h b/src/mame/includes/neogeo.h
index df674a005df..47bd68da90c 100644
--- a/src/mame/includes/neogeo.h
+++ b/src/mame/includes/neogeo.h
@@ -68,6 +68,7 @@ void neo_pcm2_snk_1999(running_machine *machine, int value);
 void neo_pcm2_swap(running_machine *machine, int value);
 
 void neogeo_cmc50_m1_decrypt(running_machine *machine, UINT16 key);
+void neogeo_ms5pcb_m1_decrypt(running_machine *machine);
 
 /*----------- defined in machine/neoprot.c -----------*/
 
diff --git a/src/mame/machine/neocrypt.c b/src/mame/machine/neocrypt.c
index 3b7885388cb..3a2df226dd2 100644
--- a/src/mame/machine/neocrypt.c
+++ b/src/mame/machine/neocrypt.c
@@ -1516,4 +1516,53 @@ void neogeo_cmc50_m1_decrypt(running_machine *machine, UINT16 key)
 
 }
 
+/* the ms5pcb encryption is slightly different, there are 2 possible approachs
+   we can take */
+
+#if 1
+// if using key 0x1543 (same as mslug5) we need a different bitswap here
+int m1_alt_address_scramble(int address/*, UINT16 key*/)
+{
+	int block;
+	int aux;
+	UINT16 key = 0x1543;
+
+	aux = address ^key;
+	aux = BITSWAP16(aux, 11,0,2,5,12,7,4,9,10,8,3,14,15,6,13,1); // only 1 64k block, so...
+	aux ^= m1_address_0_7_xor[(aux>>8)&0xff];
+	aux ^= m1_address_8_15_xor[aux&0xff]<<8;
+	aux = BITSWAP16(aux, 7,15,14,6,5,13,12,4,11,3,10,2,9,1,8,0);
+	return aux;
+}
+#else
+// using key 0xa528, we can rearrange the rom first..
+int m1_alt_address_scramble(int address/*, UINT16 key */)
+{
+	UINT16 key = 0xa528;
+	address = BITSWAP16(address, 1,13,12,4,7,6,2,10,15,5,0,11,8,3,14,9);
+	return m1_address_scramble(address, key);
+}
+#endif
+
+
+void neogeo_ms5pcb_m1_decrypt(running_machine *machine/*, UINT16 key*/)
+{
+	UINT8* rom = memory_region(machine, "audiocrypt");
+	size_t rom_size = 0x80000;
+	UINT8* rom2 = memory_region(machine, "audio");
+
+	UINT8* buffer = malloc_or_die(rom_size);
+
+	UINT32 i;
+
+	for (i=0; i<rom_size; i++)
+	{
+		buffer[i] = rom[m1_alt_address_scramble(i)];
+	}
+
+	memcpy(rom,buffer,rom_size);
+
+	memcpy(rom2,rom,0x10000);
+	memcpy(rom2+0x10000,rom,0x80000);
+}