Sound Hacking/Game Boy

Simple Triggers

Game	Developer	Music Trigger + Comments
Action Man: Search for Base X	Natsume	`maincpu.b@CF30 = 0xXX` `01` = stop sound, `03~19` = music
Alien vs. Predator: The Last of His Clan	ASK Kodansha	`maincpu.b@C786 = 0xXX` `08` = stop sound, `01~07` = music
Aguri Suzuki no F-1 Super Driving	Pixel	`maincpu.b@CFE0 = 0xXX` `0A` = stop sound, `01~09` = music
Chiki Chiki Machine Mou Race	Atlus	`maincpu.b@DE80=0x01; maincpu.b@DE81=0xXX` `00` = stop sound, `01~0A, 0C` = music
Cosmo Tank	Atlus	`maincpu.b@DF80=0x01; maincpu.b@DF81=0xXX` `00` = stop sound, `01~06, 20, 22, 23` = music
Croc 2	Natsume	`maincpu.b@FFA0 = 0xXX` `01` = stop sound, `03~16` = music
Dragon Warrior I & II	TOSE	`maincpu.b@C8A5 = 0xXX` `00` = stop sound, `06, 09, 0B, 0D, 0F, 11, 14, 16, 19, 1B, 1D, 20, 23, 27, 2A, 44, 79, 7C, 7F, 82, 85, 88, 8B, 8E, 91, 94, 97, 9A, 9E, A1, A4, A8, AB, AE, B1, B6, B8, BA, BC, C1, C6, C9, CF, D1, D4, E5, E8, EB, EE, F1` = music
DuckTales	Capcom	`maincpu.b@FFA9 = 0xXX` `4C` = stop sound, `21, 41~4B` = music
DuckTales 2	Make Software	`maincpu.b@FF8F = 0xXX` `00` = stop sound, `01~15` = music
Joe & Mac	Motivetime	`maincpu.b@FF81 = 0xXX` `00~06` = music
Mighty Morphin Power Rangers	Pixel, Tom Create	`maincpu.b@DE00 = 0xXX` `00` = stop sound, `01~0B` = music
Mighty Morphin Power Rangers: The Movie	Tom Create	`maincpu.b@DEE0 = 0xXX` `12` = stop sound, `01~10` = music
Power Rangers: Lightspeed Rescue	Natsume	`maincpu.b@FFA0 = 0xXX` `01` = stop sound, `03~14` = music
Power Rangers: Time Force	Natsume	`maincpu.b@C130 = 0xXX` `01` = stop sound, `03~23` = music
Tecmo Bowl	Sculptured Software	`maincpu.b@DB2D = 0xXX` `A6` = stop sound, `80~94` = music
The Smurfs	Bit Managers	`w@0xD95A = 0x4000+3*id` `01` = stop sound, `08~19` = music
Twin	Athena	`maincpu.b@D101 = 0xXX` `00` = stop sound, `21~28, 2A~33, 37` = music

Advanced Hacks

Baby's Day Out

Notes:

Each ROM bank is 4000h bytes (16 KB) large.
The game stores 3-byte pointers in various locations: 2 bytes address (into CPU space) + 1 byte ROM bank
These 3-byte pointers will be called "PtrB" below.
ROM locations below may be given in the format BB:PPPP where BB = ROM bank and PPPP = pointer into CPU space.

various ROM locations

- functions -
Load Single Track:      4401 (register DE = pointer, register C = bank)
Stop All Tracks:        2239
Start Title (1st boot): 0251 (set C0ED~EF = 04 40 0A, then call 2288)
Start Title (return):   02D6 (set C0ED~EF = 04 40 0A, then call 22EB)
Stage intro load:       2339
Stage BGM load:         08CD

- other data -
Level Pointer Bank:     05:4000 (ROM offset 14000)
Level Header Pointers:  05:4004, 3 bytes each (2 bytes pointer, 1 byte bank)
Level Header:
                        3 bytes: ?? (some PtrB)
                        3 bytes: music PtrB
                        6 bytes: level password
Song Banks:             0A:4000 (ROM offset 28000) ~ 0D:4000 (ROM offset 34000)
                        Song headers begin at xx:4004 with 3 bytes per header. (1 byte = ??, 2 bytes = pointer)
                        Song offsets are BB:4004, BB:4007, BB:400A, etc.
        Bank 0A         2 songs
        Bank 0B         5 songs
        Bank 0C         1 song
        Bank 0D         1 song

Example song pointers:
        Title           0A:4004 (bytes 04 40 0A)
        Stage 1 Intro   0C:4004 (bytes 04 40 0C)
        Stage 1 BGM     0B:4004 (bytes 04 40 0B)
        some song       0A:4007 (bytes 07 40 0A)

misc. info

Level load routine:
        1. base pointer (e.g. 4004, points to "Level Header Pointers") into RAM CC23~CC24
        2. read that PtrB (e.g. 05:4B80) -> result into RAM CC25~CC27
        3. take CC25~CC27, add 3 to get music PtrB -> C0ED~C0EF
        4. call subroutine 22EB: stops all music, copies C0ED~C0EF -> D729~D72B
        5. start music based on PtrB in D729~D72B

Hacks

Silence title screen (1st boot):
        00:025E CD 88 22        CALL    2288h   ; start song via C0ED~EF
        ->
        00:025E 00 00 00        NOP / NOP / NOP

Play song on password screen:
        write PtrB of the song header to ROM offset 14B83~14B85 (e.g. bank 0A, ptr 4004 -> write 04 40 0A)

Note: The sound driver automatically loads the song pointed to at RAM D729~D72B when the GameBoy master volume (FF24) reaches 0.

Battle Bull

offset  hex patch               description
002779  3E 01 -> 3E xx          ;Replace Title music

Valid Music IDs: 01~0D

Blade

offset  hex patch               description
02AA50  3E 0E -> 3E xx          ;Replace Opening music
02B0F1  C6 01 -> C6 00          ;Freeze the Opening text scroll

Valid Music IDs: 01~10

Blades of Steel

offset  hex patch               description
004217  3E 00 -> 3E xx          ;Play music on the copyright screen
004284  C0    -> C9             ;Stay on the copyright screen

Valid Music IDs: 13~15, 1E, 27~32

Ikari no Yousai 2

offset  hex patch               description
001E50  3E 08 -> 3E xx          ;Replace Title music

Valid Music IDs: 00~0A

International Rally / It's a World Rally

offset  hex patch               description
015766  3E 36 -> 3E xx          ;Replace Title music

offset  hex patch               description
014BE6  3E 35 -> 3E xx          ;Replace Title music (JP Version)

Valid Music IDs: 36~5C (U) / 35~5C (J)

Nemesis

offset  hex patch               description
0001A6  3E 00 -> 3E xx          ;Play music on the Ultra Games logo screen
00051D  C0    -> C9             ;Stay on the Ultra Games logo screen

Valid Music IDs: 2D~39

Raging Fighter

offset  hex patch               description
00528B  3E A1    -> 3E xx       ;Play music on the Konami logo screen
005290  06 08 78 -> C3 90 52    ;Stay on the Konami logo screen

Valid Music IDs: 0C~18, A1, E8~F5, F7~F9, FB~FF

Samurai Shodown

offset  hex patch               description
000B0D  05 -> yy                ;Replace Music Bank
000B0E  12 -> xx                ;Replace Opening music
001C64  3C -> 00                ;Slow down the Opening text scroll

Valid Music IDs: 11, 12 (Bank 05), 11~1A (Bank 06), 11~1C (Bank 07)

Star Ocean: Blue Sphere

offset  hex patch               description
0040C3  3E 00    -> 3E xx
0040C5  EA 69 C9 -> CD 5E 30    ;Play Music on Enix logo screen
0040D2  D8       -> C9          ;Stay on the Enix logo screen

Valid Music IDs: 01~1E

Track & Field

offset  hex patch               description
000B59  3E 00 -> 3E xx          ;Play music on the Konami logo screen
000B91  C0    -> C9             ;Stay on the Konami logo screen

Valid Music IDs: 43~4A

Wayne's World

offset  hex patch               description
002474  09 -> xx                ;Replace Title Music
00110B  34 -> 00                ;Stay on the Copyright Screen

Valid Music IDs: 00~0F

World Bowling

offset  hex patch               description
00578A  3E 43 -> 3E xx          ;Replace Title Music

Valid Music IDs: 41~48