Homebrew Saturn emulation using Cotton/Guardian Force testing and debug

[HimJow]

Great tutorial, thanks! I’ve never really had any major issues with Saturn_2_NSP_v1.2—well, a few minor ones—but overall, I've been able to get all my games running smoothly (aside from the fact that most run better when overclocked). I even got the latest Castlevania SOTN (Ultimate) and Princess Crown working without a hitch. So, I’m mainly interested in version 1.3 as a backup. If you manage to get a successful NSP working with it, let me know!

Post automatically merged: Aug 21, 2025

Hey @princessvini , thanks for sharing your method—really appreciate you laying it out.

I want to test this myself and was wondering if it could be simplified a bit. Would this work just as well?

Create NSP for Disc 1 → Play → Save
Create NSP for Disc 2 → Launch once → Quit
Use JKSV to dump Disc 1’s save
Inject Disc 1’s save into Disc 2’s save folder using JKSV
Launch Disc 2 → Continue your game

Not trying to question your approach—just exploring the cleanest way to get it working.

i hope this disc save file transfer method work , praying it will so i can play sakura taisen and panzer dragoon on my switch

 

[dragonz]

It is confirmed that as you said, if you use the 1.0 patch, it can run well. However, if you use the 1.1 patch, after debugging, you can only get an error warning or a black screen.

if you had take a wild guess, why do you think 1.1 patch can't be processed into a .nsp and work?

 

[hotcofe]

如果您大胆猜测一下，您认为为什么 1.1 补丁不能被处理成 .nsp 并起作用？

It's not that version 1.1 can't be made into an NSP; it's just that there are issues with its operation. As I mentioned before, this emulator is an incomplete version of the SSF, and many features aren't implemented, such as the inability to access BIOS files. We're also unclear about the changes made to the ROM in the 1.1 patch, so compatibility issues aren't ruled out, and we might even need to tweak the config files for testing. Honestly, this could take a long time, and there's a chance the game won't run at all due to the emulator's inherent incompleteness.
By the way, regarding the issue you mentioned in your previous post about needing to export and import save files using JKSV for a multi-disc game, this isn't necessary. Simply create an NSP file with the same title ID for each disc. After completing the first disc's game content, delete the game and install the second disc's content. The game will automatically inherit the previous save file.

 

[Olinnae1]

Wow, this is amazing!

Just to clarify:

You used Team Medusa’s version 1.0 patch, right?
Not the latest release?

And you managed to get the PSP English voices working? That’s awesome!

What settings did you use for Saturn2NSP?
(e.g. 4MB RAM expansion, widescreen support, etc.)


Also, does Saturn2NSP v3 have an option to disable the Cotton menu screen from always appearing?
I know that option exists in Saturn2NSP v2, but I haven’t seen it in v3.

Yes it is version 1.0, this romhack is the one with English voice acting pulled from the PSP version!

The v1.3 of Saturn2NSP only really has two options and that's if you want to use the 4MB Ram Expansion and if you want widescreen. For this game I used the 4MB expansion (I think it might need it?) and kept widescreen off. I personally don't Like how games can be stretched by it and without the option to turn off the emulator menu, with widescreen on the menu blocks some of the screen. Because yeah that's the unfortunate part about v1.3 is there is no option to turn off the menu, which I'm not sure why not. It's unfortunate because v1.2 is not an option for me

 

[dragonz]

i hope this disc save file transfer method work , praying it will so i can play sakura taisen and panzer dragoon on my switch

I got it to work in a much easier way using DBI. Just go to saves and copy them and paste the to them to disc 2 NSp.

Post automatically merged: Aug 23, 2025

Yes it is version 1.0, this romhack is the one with English voice acting pulled from the PSP version!

The v1.3 of Saturn2NSP only really has two options and that's if you want to use the 4MB Ram Expansion and if you want widescreen. For this game I used the 4MB expansion (I think it might need it?) and kept widescreen off. I personally don't Like how games can be stretched by it and without the option to turn off the emulator menu, with widescreen on the menu blocks some of the screen. Because yeah that's the unfortunate part about v1.3 is there is no option to turn off the menu, which I'm not sure why not. It's unfortunate because v1.2 is not an option for me

Yeah that's why I'm planning on making it with v2 to remove the side menus appearing.

Thanks! Now I need a refresher on how to patch saturn games . lol

 

[Slayer14]

I have Extended 1.5 & Ultimate 1.0 running just fine on my switch

 

[dragonz]

Yes it is version 1.0, this romhack is the one with English voice acting pulled from the PSP version!

The v1.3 of Saturn2NSP only really has two options and that's if you want to use the 4MB Ram Expansion and if you want widescreen. For this game I used the 4MB expansion (I think it might need it?) and kept widescreen off. I personally don't Like how games can be stretched by it and without the option to turn off the emulator menu, with widescreen on the menu blocks some of the screen. Because yeah that's the unfortunate part about v1.3 is there is no option to turn off the menu, which I'm not sure why not. It's unfortunate because v1.2 is not an option for me

Got it working — thanks!

I used Saturn2NSP v1.2, and I can confirm that:

The menus can be disabled

Save functionality doesn't work

Everything else runs fine!

 

[Olinnae1]

Got it working — thanks!

I used Saturn2NSP v1.2, and I can confirm that:

The menus can be disabled

Save functionality doesn't work

Everything else runs fine!

Wonderful!

 

[dragonz]

Wonderful!

WHoly crap — a new secret has been found!!!

As I was typing this and taking a photo of the menu screen, after about 5 to 10 minutes, a loud voice suddenly started talking — scared the hell out of me!

I don’t think anyone’s ever discovered this before. Maybe people found the voice lines through hacking, but probably assumed they were unused assets…
It honestly sounded like young Maria!

 

[Olinnae1]

WHoly crap — a new secret has been found!!!

As I was typing this and taking a photo of the menu screen, after about 5 to 10 minutes, a loud voice suddenly started talking — scared the hell out of me!

I don’t think anyone’s ever discovered this before. Maybe people found the voice lines through hacking, but probably assumed they were unused assets…
It honestly sounded like young Maria!

Dude the exact same thing happened to me while I was typing out my report earlier! I was gonna try looking up if anyone knows about it but haven't gotten around to it yet. lol that's funny the same thing happened to you. But I guess that's one voice line that either never got translated or the Team Medusa who made the rom hacked missed it, unsure.

 

[hotcofe]

Hey guys, I have some good news. I made some changes to saturn2nsp V1.3, and now it is possible to remove the menu icon in the lower left corner when in widescreen mode. If you want to try it, I can share it with you.

 

[dragonz]

Hey guys, I have some good news. I made some changes to saturn2nsp V1.3, and now it is possible to remove the menu icon in the lower left corner when in widescreen mode. If you want to try it, I can share it with you.

I already fixed that with V1.2 and I don't like widescreen because it stretches the image but, please share it because some people don't mind.

 

[Knight of Time]

Hey,

So quite a while ago, I was successful in porting Sonic 3D Blast to my Nintendo Switch, but these days, for some reason after I unintentionally deleted it from the console, I've been suddenly having great difficulty getting the game back on.

I've tried multiple methods, including injecting it into one of the Cotton games and making a standalone version of the game, but nothing seems to be working. What is everyone using to install a Sega Saturn game these days?

I have a slight feeling I might need to get the sigpatches updated here, though with the fact I updated my Switch firmware to 20.0.3 and updated Lockpick to version 1.9.15, something just isn't adding up on my end.

Anyway, can someone please help me out? I'm hoping I can play Sonic 3D Blast on it again in the not-too-distant future.

 

[hotcofe]

I already fixed that with V1.2 and I don't like widescreen because it stretches the image but, please share it because some people don't mind.

This is just a fix for some issues with saturn2nsp v1.3. Perhaps someone needs this functionality, so I'm sharing it with everyone for testing. However, it's important to note that since this is just a test version, I haven't made any thorough changes. Just select "cotton2.nsp" in the "select emu" option. I also hope everyone can provide feedback after testing. https://mega.nz/file/rZ11ybLI#C_TA5ft6bHYDThbwalF6X1tFpgD50ZmHwuWEvOwt3iU

Post automatically merged: Aug 23, 2025

Hey,

So quite a while ago, I was successful in porting Sonic 3D Blast to my Nintendo Switch, but these days, for some reason after I unintentionally deleted it from the console, I've been suddenly having great difficulty getting the game back on.

I've tried multiple methods, including injecting it into one of the Cotton games and making a standalone version of the game, but nothing seems to be working. What is everyone using to install a Sega Saturn game these days?

I have a slight feeling I might need to get the sigpatches updated here, though with the fact I updated my Switch firmware to 20.0.3 and updated Lockpick to version 1.9.15, something just isn't adding up on my end.

Anyway, can someone please help me out? I'm hoping I can play Sonic 3D Blast on it again in the not-too-distant future.

Is this the game? I used saturn2nsp to make a test, and it ran fine, with no lag or popping sounds. You can also try making it.

 

[Knight of Time]

This is just a fix for some issues with saturn2nsp v1.3. Perhaps someone needs this functionality, so I'm sharing it with everyone for testing. However, it's important to note that since this is just a test version, I haven't made any thorough changes. Just select "cotton2.nsp" in the "select emu" option. I also hope everyone can provide feedback after testing. https://mega.nz/file/rZ11ybLI#C_TA5ft6bHYDThbwalF6X1tFpgD50ZmHwuWEvOwt3iU

Post automatically merged: Aug 23, 2025

Is this the game? I used saturn2nsp to make a test, and it ran fine, with no lag or popping sounds. You can also try making it.

Yes, that's it.

I just tried the new version of saturn2nsp and started a rebuild of the game, but at one point, I got stuck again as shown here:

So yeah, what is going on here? I'm quite baffled.

 

[hotcofe]

是的，就是这样。

我刚刚尝试了新版本的 saturn2nsp 并开始重建游戏，但在某一时刻，我再次卡住了，如下所示：

View attachment 523744

那么，这到底是怎么回事？我有点困惑。

如果您确认所有操作均正确，建议您更换一个ROM再试一次。

 

[Knight of Time]

如果您确认所有操作均正确，建议您更换一个ROM再试一次。

Yes, I am very sure I'm on the right track here, but the program is still asking for the test_saturn file. Does that file even exist?

 

[Olinnae1]

Hey guys, I have some good news. I made some changes to saturn2nsp V1.3, and now it is possible to remove the menu icon in the lower left corner when in widescreen mode. If you want to try it, I can share it with you.

Thanks that is awesome! Thanks. So I just need to select cotton 2 to hide the menu icon? and does that work even if I have widescreen off?

 

[hotcofe]

Yes, I am very sure I'm on the right track here, but the program is still asking for the test_saturn file. Does that file even exist?

"test_saturn" is just the file name used during the generation of the nsp file. The final generated file does not have this name.

Post automatically merged: Aug 24, 2025

Thanks that is awesome! Thanks. So I just need to select cotton 2 to hide the menu icon? and does that work even if I have widescreen off?

Yes, just select "cotton2.nsp" and the display effect will also apply to the original aspect ratio. In addition, I don't know how the effect is when you use it, can you tell me about it?

 

[dragonz]

Here are the v1.1 changes if anyone is curious:

• Increased overall performance in the game (increased CPU frequency);
• Removed voids at the top of the screen in some locations; 
• Improved “Hard Mode” (enemies deal 2X damage); 
• Added translucency of clouds against the background of the moon (flickering); 
• Added translucency to the large window in Count Dracula's apartment; 
• The name of the current location is now displayed in teleport rooms; 
• Fixed the flame palette in the prologue (before the picture burns); 
• Fixed a bug with the palette of a huge skull in an inverted castle; 
• Fixed minor bugs in pop-up messages;

So those are features you wont have, nothing really to cry about.

I really wish the voids were resolved in our "Ultimate" version. That said, this list suggests that one—or possibly several—of these features might be triggering the crash on the Switch version. If I had to make an educated guess, I'd point to "CPU frequency" as the likely culprit.