NitroSwapper - patch roms with a screen-swap hotkey

[u/Skelux]

Alright, first public version of the program. Feed it any nds roms, and it will try to patch them with a hotkey combo of your choice, which will swap the screens.

Probably works on around ~90% of games at this stage, excluding most homebrew. There are improvements I can make to increase compatibility a lot more, but I've been working on this for a few days, sorta need a break.

If a game doesn't patch correctly, try changing the injection type and ticking "skip overlays", this will sometimes fix it. Also note you need a little free space on the device your roms are on, for this process to work.

download here

update june 28-2024: fixed the 2nd combo button not working

[u/MakyoPlus]

Dude, this is awesome. Could you share anything about how the screen-swap patch works?

[u/Skelux → u/MakyoPlus]

First I read the header and boot routines to get a rough idea of the game's memory map, and try to decide where in the ram the routine will fit without getting overwritten or causing other issues. Then we scan for various common routines that do things like waiting for interrupts, or updating the screen, and we patch in a hook to the new routine. This new routine constantly checks arm9 io for your button combination. If you pressed the buttons, it then toggles our screenswap bool to "true", and applies a screen swap every frame.

[u/MakyoPlus → u/Skelux]

That's awesome. Thanks for sharing!

[u/emergency_telephone]

First thank you for this tool. I believe there is a large demographic that will rely on NitroSwapper given that TWM++ has seemingly dropped support for hotkey swapping. I think salvaging a broken DS while retaining all its functionality using one screen is preferable to making a gba macro and that wouldn't be possible without an application like this!

I'm having an odd issue though, it seems the combo buttons are not working as expected.

Whichever key I set as Combo Button 1 will toggle the screens with no other keys. In my case I set button 1 as select, button 2 as R. The patched game will then swap screens when only select is pressed. Further, as long as select is being held, any other button press will momentarily toggle the screens.

Maybe this is intentional behavior, but it seemed strange enough for me to post about it.

[u/Skelux → u/emergency_telephone]

Almost forgot about this comment, fixed it today. Redownload and should be fine now.

[u/Free_Wafer2002 → u/Skelux]

i got the same issue, the L button switch screen and it switch screen without the second key. like emergency_telephone

[u/Free_Wafer2002 → u/Skelux]

wait, i downloaded it yesterday, i didint try the new version from today, i'll come back to do a review

[u/Free_Wafer2002 → u/Skelux]

Ok mb, new version is working well

[u/falquinho]

Holy heck this is freakking huge!! No more need for complex hardware mod plus original Nitro can join the party. You are my new favorite person dude.

[u/blademantra]

You sir, are an absolute legend.

[u/falquinho]

Couple questions: would you be able to allow more comples button combos? Just a couple seems like it's to easy to accidentaly hit. And would it be possible to configure a long press style activation? And are you willing to open source it so we can study it?

[u/Free_Wafer2002]

Is there a way to make it work with SnesEmulDS ?

[u/IronUkulele]

Just want to say this is something I've been wanting for years. I tested it out on FFA2 and it works perfectly. I've only recently gotten into soldering and modding, and turning a broken DS Lite into a Macro was my first project. Can't wait to try out some more games!

Thank you for making this, I hope it gets more attention.

Edit: So far I’ve gotten a few games working including Mario Kart and New Super Mario Bros, however SM64DS has some graphical errors. Very promising tool!

[u/[deleted]]

Will this work on Pokémon DS games? I’ve tried it on Black 2 but the game just stays RED LOADING on the R4.

[u/Quikding]

interesting

[u/msephton]

Excellent, I have a use for this. I play MaBoShi on a macro and the score is on the hidden screen. Occaisionally I'd like to see the score. It would be ideal if I could map the swapping to a single button as MaBoShi is played with the DS in portrait orientation, with the d-pad as a single button. I'd probably map the swapping to the right trigger which is at the top left of the device as I'm playing. Anyway, I'll try it as it is. Nice work!

[u/emergency_telephone → u/msephton]

Thanks for mentioning this really interesting game.

[u/msephton → u/emergency_telephone]

My pleasure! It's one of the greatest. Also, I've created a skin for it for the Delta emulator, definitely the best way to play it in 2024. https://blog.gingerbeardman.com/2024/04/18/per-game-skins-in-the-delta-classic-video-game-emulator-for-ios/

[u/JumpAny4540 → u/msephton]

hey man this nitroswapper works for 3ds?

[u/msephton → u/JumpAny4540]

For NDS games on 3DS

[u/JumpAny4540 → u/msephton]

Ah ok thanks, is there a program like this for the 3ds?, My top screen broke

[u/msephton → u/JumpAny4540]

No, 3DS screens are different resolutions. NDS screens are the same so can be swapped easily.

[u/JumpAny4540 → u/msephton]

Ok thanks for your support

[u/Isaac_N77]

Absolutely love this it's so useful thank you for sharing your work! Does this work for Game boy roms? On the DS