Mario vs Luigi

This page documents how to play MvsL hacks and objects that work in MvsL.

Modding MvsL is significantly more difficult than modding Singleplayer levels. If you're just getting started with modding the game, you might want to start here

FaQ

How do I play Mario vs Luigi hacks?

• The easiest way to play an MvsL hack on real hardware is by using “Multi-cart”
  • This requires that you own two flashcards (such as an R4 Card).
  • To set this method up, simply put the same ROM on both flashcards. Then, in the game, choose the option to “Compete with another New Super Mario Bros. Owner” and play MvsL as you normally would.

• If you do not have access to two flashcards, then you have two, more difficult, options remaining
  • Your first option is to try and use a hacked NDS firmware that bypasses Download Play's signature check
    1. Download firmware.nds and put it on your flashcard.
    2. Open this ROM on the DS you will launch Download Play from.
    3. Now, eject the flashcard from the DS you just ran the ROM on. (This will not cause your DS to freeze)
    4. Finally, put the flashcard back in the other DS.
    5. Once you have done this, you can run the ROM of the MvsL hack and select “Play with someone who doesn't own New Super Mario Bros”
       • If the firmware ROM does not work on your flashcard, try this one instead.
  • Your final option is to use normal DS Download Play with “DLP Mode” in NSMBe 5
    1. Open a clean (unedited) ROM
    2. Open it in NSMBe
    3. After you open the ROM, go to Tools and check “Enable DLP-friendly mode”
    4. Now, you can make whatever changes you want to the ROM
    5. When you're done, you can play with another DS through DS Download Play like you normally would using the “Play with someone who doesn't own New Super Mario Bros” option
• If the game hangs at the Nintendo logo, you might have missed a step. Double check you did everything and try again with another clean ROM
• If the DS freezes with a black screen after you select a level it can mean one of two things:
  • Your flashcard is not compatible with this method
  • There's something wrong with the level that is making the game freeze

My level crashes, what do I do now?

• If you are not using any Code Hacks, then here are some things to consider
  1. Have you changed any object banks? This causes MvsL to crash so you need to change the object banks back to whatever the level had originally.
  2. Double-check that you are not using an object that has been confirmed to crash MvsL. There is a table later on this page that shows what objects are compatible with MvsL.
  3. Have you changed the number of Battle Stars that are in the level? Changing the number of Battle Stars in a level can cause MvsL to crash, and you will need to restore the original amount of Battle Stars the level had.

My level crashes, but I'm using Code Hacks!

• Even with Code Hacks, not all objects work in MvsL. Take a look at the table at the end of the page to see if all of the objects you're using are compatible with MvsL.

My level makes us de-sync, what's going on?

• Because of the nature of how multiplayer works in this game, the Random Number Generator seed is only synchronized once when the connection is established and only the input is synchronized during gameplay so it is required that each console knows what the other console is doing. If something is coded in a way that won't account for the other console, the multiplayer state of the game will be compromised. For example, if it happens that an enemy does not properly handle multiple players it might just check the variables of the player of its own console, causing it to read a different value on each console. This causes the enemy to act differently on each DS, thus causing a de-sync.
  
  Implementation example:
  

  // Enemy reads only the position of its own console player
  playerPositionX = Game::getPlayer(Game::localPlayerID)->position.x;
  // Now the position that was read is different between both consoles
  // for this enemy and he will behave differently for each console!
  // This is very bad!
  
  // A solution would be to get the position of the closest player
  playerPositionX = enemy->getClosestPlayer(nullptr, nullptr)->position.x;
  // This way, it gets the closest player instead of its console player

Object Compatibility (Vanilla)

• These objects will work in MvsL regardless of if you are using code hacks
• Most of the objects in this list are objects that are already used in MvsL

Object Compatibility with Code Hacks

• This spreadsheet is based on the MvsL Hacking Starter Pack
• There are 4 kinds of compatibility
  • Works: This object completely works in MvsL
  • Partial: Some parts of this object do not work in MvsL. The notes column will mention what doesn't work
  • N/A:  The object does not load but it also does not crash the game
  • Crash: The object crashes the game when loaded. See the notes for possible workarounds.