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Sega Mega Drive Hacking Help

Technical discussion which is not directly related to VGM files. Talk about Hardware and Software.

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Sega Mega Drive Hacking Help

Post by Gnome »

Original topic from Project2612: https://project2612.org/phpbb3/viewtopic.php?f=2&t=551

This topic is dedicated to requesting help for ripping VGMs from the Mega Drive/Genesis games that aren't accessible via the normal means (such as the sound test), as well as posting your hacking findings and notes for the sound drivers.
These days I mostly maintain old/faulty packs.

Post by Kaminari »

I'd love a music trigger for Snatcher MCD, but I don't know if any progress has been made since the last time I asked (must have been about 7 years ago).
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Post by xKingDukeNukemx »

Kaminari wrote:I'd love a music trigger for Snatcher MCD, but I don't know if any progress has been made since the last time I asked (must have been about 7 years ago).
Did you mean a full VGM rip of Snatcher on Sega CD? That's been out for awhile now on YouTube. https://youtu.be/w6MGP5Ql-mQ

SynaMax was the Ripper.

FYI, I don't mean to throw this here off topic. But I hope someone here can help you with hacking Sega Genesis games.
Nukem All

Post by Kaminari »

Thanks a lot for the heads-up! I wasn't aware someone else had finally completed it. One less rip to worry about :bomb:
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Post by Dario011 »

When I see that I have to do things with a debugger to get some music that does not normally sound in a game, it's a pain in the ass.

While I was re-ripping Shinobi III (as well as its prototypes), I found that in the oldest prototype [The Super Shinobi 2] (which in general is a very incomplete game, but with a VERY DIFFERENT music from the final version), there is a song, from ID 06:???? that is disabled, but according to a video shows that modifying the ROM brings out the hidden song, the thing is, how do I do that?

The video is this one (in which it also puts information on how to modify the ROM to make it play, replacing the first song): https://www.youtube.com/watch?v=KnQbfBkiXuo
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Post by Dekyo-NO »

I just did this:

1. Open the ROM with HxD
2. Press ctrl+g and go to the music pointer offset 636F8
3. Replace "00 06 38 98" with "00 06 A7 56"
4. Save and test
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Post by (Jazz) Jackalope »

I need help, s'il vous plait, to either find a way to change the starting level for Chuck Rock, or make a Krisalis engine game dynamically play music on command like an SMPS game. Can it be done?
I'm trying to add information found on the forums easier to find on the wiki. If I forget to credit you, please let me know (or edit the article if you don't want to wait).

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Post by ValleyBell »

Have a look at the hacking information for Bill's_Tomato_Game.
That game is using the Krisalis sound driver.

The sound RAM may be at a different location though.
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Post by The789Guy »

I would like some help finding music pointers for True Lies. The game uses Maxmus, Beam Software's sound engine by Trevor Nuridin.
I'm just your average joe who basically contributes random crap to the site. I mainly rip soundtracks by Western composers because they don't get as much love.
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Post by The789Guy »

I also need help finding music pointers for Cutthroat Island and Foreman for Real, both of which use Tony Williams' sound driver. Thing is, not only do they use different builds, but the former doesn't list the version of the driver.

https://segaretro.org/Sound_Images
I'm just your average joe who basically contributes random crap to the site. I mainly rip soundtracks by Western composers because they don't get as much love.
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Chuck Rock

Post by (Jazz) Jackalope »

ValleyBell: Thanks! After I realized what I was doing wrong (was looking at ROM instead of RAM), I was able to find the sound trigger. (I also made some progress on Bugs Bunny in Double Trouble, which I'll put in a separate post if that's okay because it's long.)

Values go in $FF0014
  • Stop music: 1
  • Title: 2 to 22
  • L 1: 23 to 31
  • L 2: 32 to 41
  • L 3: 42 to 50
  • L 4: 51 to 57
  • L 5: 58 to 67
Each slot starts at a different portion of the overall song, plays a different tempo, or both.

Problem is that I don't feel like checking every slot to ensure there's no unused music. But in this case, there probably isn't.
I'm trying to add information found on the forums easier to find on the wiki. If I forget to credit you, please let me know (or edit the article if you don't want to wait).

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Bugs Bunny in Double Trouble

Post by (Jazz) Jackalope »

0414: The number changes to hex 83 when I play sfx in the cheat menu. Setting it manually doesn't make sfx play. Instead, it seems to cause music/sfx playing to move to 043A (hex 83) and 043C (song/sfx, see 0416 below)... actually, both areas activate for some sfx but not others.

Fascinating: at slot 46, the Play Sound command dutifully played ARENABUG, the next slot in line. When I reached the music, the sfx further moved to 051E/0520. So it seems to me the hex 83 is to let the game know that sound playing area is in use, so it can use another.

0404/5: Set the former to 00 and it will make the current sfx play... repeatedly... and you can't turn it off? Multiple sound play areas appear to be activated.

0416 contains the currently playing song/sfx. But it's not a trigger; setting it doesn't cause the sound to play, and 0404 seems to ignore it.

SFX are noted in (parentheses).
  • 00 TITLE
  • 02 CAMEOS
  • 03 LEVCOMP
  • 04 LEVFAIL
  • 05 BUGSPACE
  • 06 BULLYBUG
  • 07 BONUSLEV
  • 08 GAMECOMP
  • 0B MRVANGRY
  • 0C BUGSCONT
  • 0D INVULNER
  • (0E running)
  • (0F boom)
  • (10 stopped running)
  • (11 running alt?)
  • (12 whiff)
  • (13 lion)
  • (14 thump?)
  • (15-29)
  • (2A pause)
  • (2B)
  • (2C cage)
  • (2D-31)
  • (32 menu sound)
  • (37 nyah nyah nyah-nyah nyah
  • (38 took hit)
  • (39-3A)
  • 3B ARENABUG
  • 3C BUGHAUNT
  • 3D DUCKRABB
  • 3E ARABIAN
  • 3F KNIGHTY
  • (40-59)
The sound slots in the cheat menu stop at 76 (59). Also, I actually would not record from that menu since some things sounded off from in-game. That, or it happened because of previous sound plays.

FA76 is the larger number used by the timer. It can go as high as 7F (80 and above overflows? and launches the demo immediately). Set at 7F, it lasts a little longer than two loops' worth of some of the longer songs, like BULLYBUG.

To work in Blastem, it must be specified as a byte:

Code: Select all

set [$FFFA76].b 121
I'd love to actually have the sound trigger so I can check for unused music, but I don't know what I'm looking for and all I found otherwise is more timers, button press readers, and such things. Hoping what I've found is enough for someone more experienced to zero in on the trigger, if one exists.
I'm trying to add information found on the forums easier to find on the wiki. If I forget to credit you, please let me know (or edit the article if you don't want to wait).

WIPs: 2023-10-30
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Post by (Jazz) Jackalope »

Now that I know better what I'm doing, I attempted to find a music trigger for Toejam and Earl. No luck yet, but I found the general area in 68k ram: FFFE00.
I'm trying to add information found on the forums easier to find on the wiki. If I forget to credit you, please let me know (or edit the article if you don't want to wait).

WIPs: 2023-10-30
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