Tinker

3DS Homebrew Theme Manager for Shufflehax/Menuhax/Themehax. Heavily inspired by CHMM2 and made using Rinnegatamante's lpp-3ds. Please post bug reports or questions in the GBATemp development thread, I'm more likely to see them there.

Installation

Download the .zip file here.
Extract it to the 3ds folder on your SD Card; the path should look like this: /3ds/Tinker/
Place your themes in a Themes folder at the root of your SD Card, just like you would for CHMM2. Themes should each have their own folder with their contents in them like so:

/Themes/Theme1/
/Themes/Theme2/
etc

(Theme1, Theme2, etc are just examples of theme names, your theme folders can be named anything, as long as they are in /Themes/)

NOTE: If you have a Japanese 3DS console, there is a bug in the 3dsx file which stops Tinker from running. You'll need to download 15avaughn's patched Tinker.3dsx file and replace /3ds/Tinker/Tinker.3dsx with that patched Tinker.3dsx. Furthermore, launching 3dsx files doesn't work either, meaning after you press A to install a theme from the popup, you need to manually exit out of Tinker, enter Menuhax Manager and select Install Theme. These problems are only present on Japanese 3DS's.

Usage Guide

Browse the available themes on the bottom screen using the DPad arrow keys.
Press Y while over a theme to bring up a theme preview on the top screen. Once Y is pressed, the top screen portion of the preview should appear. It will last about 5 seconds, then the bottom screen portion will appear. That will disappear after about 5 seconds and you should be able to move again.
Press A to apply the theme, this will bring up a confirmation dialogue. Pressing A will open up Menuhax Manager, choose Install Custom Theme to install the theme. Pressing B will close the dialogue box and the theme will not be applied.
Press the Start button to exit the application and return to the Homebrew Launcher. This glitches out if you're using the Gridlauncher so you'll have to hold Right Bumper+Left Bumper+Down Arrow+B button to exit.

Things to note

You can't use the touchscreen or circlepad to navigate, circlepad is planned for a future release but touchscreen support probably won't happen because effort.
The Settings button (blue circle with the gear in it) is inaccessible for now, that'll be implemented later when I actually find settings worth implementing.
No support for theme shuffling just yet, I'm looking into it to see if it's possible to implement.
This only works for Menuhax theme implementation, use CHMM2 if you're looking for standard custom theme installation.
If you have a very large number of themes then the app will likely hang at a black screen on start up for a long time as it loads them all

Changelog

v1.0.2 (3/1/16)
Introduced proper error dialogue for when Tinker detects Menuhax Manager is not installed, rather than having it throw a Lua-style error.
Added banners for use with Masher's Gridlauncher (a standard one which is used by default, and a 3dsflow one which can be used by renaming the standard one to something else, and renaming the 3dsflow one to "Tinker-banner-fullscreen.png")
Added a .3ds file - this has not been tested at all, I have no idea if it works or what it does. I don't have any means of testing it currently.
v1.0.1 (1/1/16)
Introduced proper error dialogue for when no themes are detected, rather than having it throw a Lua-style error.
v1.0.0 (31/12/15)
Initial release

Credits

Rinnegatamante for lpp-3ds and also for their incredible work on CHMM2 and Sunshell. Without all of those things this project would not be possible.
ihaveamac for guidance and support in getting features like .3dsx launching working.
15avaughn for his patched Tinker.3dsx file which works on Japanese consoles.