Homebrew ROM Hacks download play?

[IC_]

I made a rom hack for Mario Kart DS but when I try to play multiplayer through Download Play the other DSes freeze at the Nintendo logo (probably because it's not signed from what I know). I've been thinking that if there was a homebrew to run a patched Download Play so it can download unsigned files it would be possible to run it on the other DSes with HaxxStation or by running it from a flashcart then removing it and repeat on other DSes. Should that be possible or I'm completely wrong?

 

[FAST6191]

The download play is a separate file within the game (typically something called utility.bin or [something].srl, and often in a folder in a folder called dwc or just in the main directory of a game) and is unaffected by general ROM hacks (save for you messing with the wifi sending routine). On the flip side if you tried to edit the main game levels and the download play aspect did not get changed it could cause some problems -- plenty of wifi issues happened when people raced around different tracks.

There are certain flash carts with issues sending the download play client. I don't know the exact issue (it was a point of contention at one point in the early days of DS flash carts and I mostly just laughed at people claiming they cared -- most flash carts were the same at this point and utterly minor differences got pounced upon to find "the best").

Most games don't work well once you eject them, indeed other than a few homebrew programs (like the ROM dumper) it tends not to. Also if any of those are a DSi or 3ds then it will sense the eject and do what it does when it senses that (typically pause and go back to a menu/error screen).

If you did edit the actual download play file then I would expect errors, including black screens. Fixes then being run flashme on all the DSes you want to join in. Or try to load it via that new HaxxStation stuff.
Equally depending upon how much you are willing to spend then almost any flash cart you can find will run Mario Kart DS (it is a fairly early game after all) which means you can have a lot more extensive mods made for it. If you are mainly on DS/DS lites then even better. I am sure some flash cart seller somewhere would be delighted to offload a bunch of old flash carts that stopped being updated long before DS games stopped being released and thus don't sell. If you are on a 3ds then I believe there are things to allow certain flash carts to run if you don't want to spring for something with R4 and a lot of pointless extra words in the title_.

 

[IC_]

The download play is a separate file within the game (typically something called utility.bin or [something].srl, and often in a folder in a folder called dwc or just in the main directory of a game) and is unaffected by general ROM hacks (save for you messing with the wifi sending routine). On the flip side if you tried to edit the main game levels and the download play aspect did not get changed it could cause some problems -- plenty of wifi issues happened when people raced around different tracks.

There are certain flash carts with issues sending the download play client. I don't know the exact issue (it was a point of contention at one point in the early days of DS flash carts and I mostly just laughed at people claiming they cared -- most flash carts were the same at this point and utterly minor differences got pounced upon to find "the best").

Most games don't work well once you eject them, indeed other than a few homebrew programs (like the ROM dumper) it tends not to. Also if any of those are a DSi or 3ds then it will sense the eject and do what it does when it senses that (typically pause and go back to a menu/error screen).

If you did edit the actual download play file then I would expect errors, including black screens. Fixes then being run flashme on all the DSes you want to join in. Or try to load it via that new HaxxStation stuff.
Equally depending upon how much you are willing to spend then almost any flash cart you can find will run Mario Kart DS (it is a fairly early game after all) which means you can have a lot more extensive mods made for it. If you are mainly on DS/DS lites then even better. I am sure some flash cart seller somewhere would be delighted to offload a bunch of old flash carts that stopped being updated long before DS games stopped being released and thus don't sell. If you are on a 3ds then I believe there are things to allow certain flash carts to run if you don't want to spring for something with R4 and a lot of pointless extra words in the title_.

I didn't edit the download play file or any of the stuff that could cause problems with download so I don't know why it doesn't work, normal unmodified Mario Kart DS rom launched from the same flashcart will work with download play normally.

 

[FAST6191]

What did you modify the ROM with? There have been times in the past where certain tools troubled certain games with certain flash carts, Mario Kart being one of those trouble games and many popular tools of the day being the tools troubled it. If you used MKDS course modifier then some of the things it did in the past I could see causing trouble here, however I have not used the program in a while so I don't know what it is like today.

Typically it was things like overlays that got troubled but if it is was one of those overlays which sends the download play client then it could cause what you are seeing.

First thing to try is grab NDStool, extract the ROM and recreate it.
https://filetrip.net/nds-downloads/...ntendo-ds-rom-tool-ndstool-1-50-1-f29352.html

Extraction and rebuild commands should be something like

 ndstool -x *.nds -9 arm9.bin -7 arm7.bin -y9 y9.bin -y7 y7.bin -d data -y overlay -t banner.bin -h header.bin
 ndstool -c mariokartmodfix.nds -9 arm9.bin -7 arm7.bin -y9 y9.bin -y7 y7.bin -d data -y overlay -t banner.bin -h header.bin

Make sure it is just mario kart in the directory at the start of that or it will try to extract every single nds file you have there. A file called mariokartmodfix.nds should hopefully be made and you can try that.

Next method if that does not work (if you want to try tinke and crystaltile2's full extract and rebuild as well as ndstool's then give it a go) is you get to insert your modified files one by one (or at least in such a way that it does not cause a rebuild of the file system/file order) into a stock ROM.
I doubt ndsts will do it for this so time to use tinke. It should be on the right click of individual files.
If there are a lot of modified files but you know what each does and can make a proof of concept (if you edited say 10 levels but only need to put one of those in to test then then do that).

 

[Ryab]

I didn't edit the download play file or any of the stuff that could cause problems with download so I don't know why it doesn't work, normal unmodified Mario Kart DS rom launched from the same flashcart will work with download play normally.

from my experience download play freezes a lot with most flashcarts

 

[IC_]

from my experience download play freezes a lot with most flashcarts

Yeah, but it still froze only with my ROM hack and it didn't freeze with an unmodified ROM

 

[IC_]

While thinking of it now it’s possible that one of the files I replaced is too big for download play and the other consoles crash because they don’t have enough free RAM.

 

[Dentus]

DS games use signature checking which is broken the moment the ROM is opened on a computer. You could use haxxstation but I have no idea how you would send the Download content.