Hello everyone! This is my first tutorial writeup, so I may make errors. Also, this process is not well documented yet, so my knowledge still has heavy limitations and there are others out there who are far more successful at performing this task than I am. That said, none of them have written a tutorial yet, so I will go ahead and do so. Lets get Started!


I. Downloads
To make a theme, you will need:
- Theme Customization Tools by Roxas75
- ExtDataTool by Yellow8, uploaded by piratesephiroth
- a Method of loading ExtDataTool, either using Smea's Ninjhax or Installed CIA through devmenu
- a theme from the theme shop on your system.

For Audio, you will need:
- Every File Explorer by Gericom
- Audacity
- Format Factory

II. Getting Theme Files
1. Load the theme you want to modify so it is your current active theme. (Stock will not work)
2. Run ExtDataTool
3. Select the Third option. (Activate cache)
4. Select option to copy cache from extdata to SD
5. Power off 3ds, put SD card in PC

You will find two files on the root of your SD, Bodycache.bin and BgmCache.bin. Copy these to your PC in a convenient location.

III. Changing the Look of the Theme
1. Rename Bodycache.bin to body_LZ.bin
2. Run Theme Customization Tools (3DS_ThemeEditor.exe)
3. Arrow next to file -> Open -> body_LZ.bin, where you renamed it
4. This is where things get more Theme-specific. You generally want to replace the images found here with images of identical size. This is best achieved by exporting the image you want to edit, loading it into your favorite image-editing program, and modifying it to your heart's content. Once you are done, import it back into the editor.
5. Click "Simulator". This will help you to know if you have your images aligned properly. If you are modifying a theme with a panning top screen, this will not pan as the theme would.
6. Once you have the theme looking right, save the file as body_LZ.bin
7. Rename body_LZ.bin to BodyCache.bin

IV. (Optional) Changing the background music
I barely got this working. In it's current state, you cannot make the sound loop nor have the filesize exceed ~3.3Mb. With these issues, you can still change the music. I use audacity for this, it's a great sound editor worth getting.

1. Locate MP3 or WAV file with your music
2. Load it into Audacity
3. Export as WAV
4. Open Every File Exporer, file -> new from file -> Nintendo 3ds Plugin -> CTR Stream
5. Select your WAV, push play to see if it works.
6. File -> Save As untitled.bstrm
7. Rename untitled.bstrm to BgmCache.bin and place on SD card

Now, you may notice that your wav and bstrm file are exorbantly large! They may be more than 3 times the size limit! Unfortunately, wav is an uncompressed format and thus has a very large file size. You have a few options on shrinking the file size:

Spoiler: Option A - Making the song shorter

1. Load the sound file into audacity
2. Find the part of the song you don't want
3. Hit Delete
4. Export as wav

Spoiler: Option B - Making the song mono

1. Load the sound file into audacity
2. Click Track -> Stereo to Mono
3. Export as wav

Spoiler: Option C - Lower the sound quality

1. Run Format Factory
2. Under the audio drop down on the left side, click "-> WAV"
3. Click "Output Setting"
4. On the drop down, select "Low Quality"
5. In the Settings below, change Sample Rate to 11025
6. Click Ok
7. Click Add File and select your sound file
8. Hit OK, then Start.
9. Click Output Folder to get to your sound file

Unfortunately, we have not yet worked out song looping, we have! so whatever you play will only play once unless you go to the power off screen and back to home.

V. "Installing" the theme
Alright, technically you are loading the theme into the cache. It's more of a load and less of an install.

1. Boot 3ds, load the theme you want to override
2. Load ExtDataTool
3. Copy Cache from SD to extdata
4. Once it complete and goes back to the ExtDataTool Menu, hit power, then home.
5. Your Theme should have loaded!

If at this point you have no theme, or the music didn't change, here is what could have happened:

- You didn't name the files properly
- You weren't on a downloaded theme when you ran the tool
- Your theme file is invalid, make sure you saved/copied it properly and are using Theme Customization Tools for body_LZ.bin and not Every File Explorer.
- If sound isn't playing, make sure your bcstm is valid. I really don't know how to help you here.


VI. Other Stuff

I wrote this up pretty quickly, and this tutorial is based on my own experience. If anyone has any improvements for the guide, please post! I can edit the guide with any new information. Hopefully someone will figure out looping sound soon, as this is the one main thing that is missing from (public) custom themes at this point.

 

[Gavrjel]

What about the little white box in the upper left corner of the screen after creating a theme? Sometimes happens and sometimes not. Anyone knows how to fix that? I noticed that some themes don't have this kind of "bug".

 

[Scarlet]

This tool makes looping audio, and automatically gets the file sizing right for you It managed to make me a good quality menu theme that loops at about two and a half minutes.

https://gbatemp.net/threads/release-brstm-bcstm-conversion-tool-beta.378702/

 

[TheZoroark007]

How do I make .cfa files and pack them to .cia?

 

[JazzCat.CL]

I tried but i didn't worked, i think i'm gonna for something else in the future thanks anyway!

 

[felystar]

Still no way to change theme color?

 

[TeconMoon]

Hey, really stupid question here.

If I have a custom theme on my 9.5 emunand, would it be safe to do a system transfer to my 9.5 sysnand on my N3DS XL, or should I disable the theme to be safe?

I don't have any CIAs or anything else on my emunand that could cause trouble, the only thing stopping me from doing the transfer is wondering if the theme will brick it.

 

[rccdcc]

Hello I wanted to know if anyone knows why when I go to import a background and when I save and apply it to the console makes me remain a white rectangle in the upper left ? I attach a screen to better understand my problem does anyone know how to fix ? thank you​

​

 

[TeconMoon]

Hello I wanted to know if anyone knows why when I go to import a background and when I save and apply it to the console makes me remain a white rectangle in the upper left ? I attach a screen to better understand my problem does anyone know how to fix ? thank you

When you originally imported the background, did you export the original image contained in the theme and modify that or did you just import your background without editing it to be the same size as the source being replaced?

Sorry I can't think of much You may also want to give this other program a try: YATA by Rei <- this has worked pretty well for me with theme creation.

Hope this helps!

 

[rccdcc]

thanks it works but now chart using the program YATA by Rei instead of white rectangle in the upper left , Apple sets moved across the image to the left always displaying a vertical line on the right
​

 

[rccdcc]

ok i resolvet the problemo haahahahah

how to change the folders?

 

[TeconMoon]

ok i resolvet the problemo haahahahah

how to change the folders?

I'm not very good at changing folders, but what kind of folders did you have in mind?

If it's as simple as swapping out one logo for another, just make sure you leave the original folder colors in-tact when editing the picture files since the 3DS seems to change the folder colors itself.

If you want to swap out the entire picture for a completely stylized folder, I'm not too sure what the best way to proceed would be. Personally, I'd try and use Nintendo's Ice Climber theme as a base since it comes with fully customized folders already and see if you can edit it from there.

You may have better luck asking these types of questions in the Custom Theme Thread. There are a ton of very talented people there making a lot of themes that have pretty good experience

Hope that helps!

 

[rccdcc]

thanks

 

[Leslie White]

Hi ! I didn't know what to do today, so I gave theme creation a try ... It's not perfect of course, but it's weird because for some pictures of the theme, I must invert the colors so they appear right on my 3ds (blue picture file will appear yellow for example...)

But I think with some training, one can do great custom themes !

I didn't manage to change the color of the upper-screen folders (but I read something about it in this thread)

Is there a tutorial for custom theme creation anywhere ?

VOLCARONA rules !

 

[tanny]

hey guys 2 things first how do i get to root of micro sd i have new nintendo 3ds and with home menu ext data windows cant run it can u recomend a forum page? thanks first post

 

[kheldar]

This has been probably answered before but Is it possible to use this method with theme packs downloaded from the famous iso site?

 

[rsc-pl]

Can I use Custom Home Menu manager to load themes?

 

[An anime lover]

HELP PLEASE!! I have opened my sd card but the only files in there are DCIM and 3DS. No .bin files to be seen! Really want to do this so any help would be massively appreciated!

 

[SammyPoke]

I've seen some people be able to pan their custom image? Does anyone know how to do this?
(I'm gonna try this to see if I align it properly it will pan once I load the theme into the 3DS)


Guess it's not worth double posting but currently this is all very buggy. I hope it gets fixed soon. At least the instructions. . .

Why can I have only one custom .cia theme installed?

 

[Madao64]

Could someone help me out? I'm unable to save the theme i made due to a compile failure of which the causes i have no clue of how to address due to the cmd closing immediately before i could remember what the error was.

 

[SammyPoke]

Could someone help me out? I'm unable to save the theme i made due to a compile failure of which the causes i have no clue of how to address due to the cmd closing immediately before i could remember what the error was.

This tutorial is a little bit outdated I suggest you download YATA and CHMM since they do the job a lot better, and allow for multiple themes!