Magikoopa 3DS

Magikoopa
File:Magikoopa.jpeg
General
Author	RicBent
Type	Utilities
Version	2019
License	Mixed
Last Updated	2019/06/29
Links
Download
Website
Source

Magikoopa is a homebrew tool aimed at rom hackers or people who want to modify the code of an existing applicaiton.

Because of memory segmentation it is not easy to add as much code to code.bin files as we want. To allow that we insert a small loader into the padding between the executable and data section that reprotects memory to our needs to mark perviously read-write only memory as executable.

Magikoopa compiles code for 3DS games and injects it into existing code.bin files and also patches the exheader.bin file. Furthermore it allows creating hooks from existing code into custom code. It features a nice UI that displays anything that can go wrong during the compiling and inserting steps.

It even allows you to jump directly to issues in code/hooks my clicking on the issues displayed in the UI. The motivation for this is to create a NSMB2 hack with fully custom code. In theory this should work with all other games as well tho. Work in progress. Should be in a kinda working state now.

User guide

Getting started

• Build the project in QtCreator.
• Run Magikoopa in the build directory.

You can find examples on how to use Magikoopa in combination with NSMB2 here.

Hooks

Hooks can be specified with hks files in a patch's working directory. The format is similar to YAML:

hook_name_1:
type: xxx
link: false
addr: 0x00430988
func: FunctionNameHere
hook_name_2:
...

There are several types of hooks.

Type	Description
branch	Branch to a function (overwrites the original instruction).
softbranch	Branch to a function (preserves the original instruction).
patch	Patch data at an offset.
symbol	Write the address of a symbol.

The following parameters are common to all hook types:

Parameter	Description
addr	Hook address.

Branch hooks

Parameter	Description
link	true to make a BL instruction, false for B.
func	(1) Branch destination function name. This will be converted to an address using the symbol table.
dest	(2) Branch destination address.

Link and one of func and dest are required parameters.

Soft-branch hooks

Parameter	Description
func	(1) Branch destination function name. This will be converted to an address using the symbol table.
dest	(2) Branch destination address.
opcode	"pre" (branch to func/dest after the original instruction), "post" (branch before the original instruction) or "ignore" (default).

One of func and dest are required parameters.

Patch hooks

Parameter	Description
data	(1) Data to insert (in hexadecimal).
src	(2) Symbol name of data to insert.
len	(2) Length of data to insert.

data, or both src and len, are required parameters.

Credits

Thanks to:

• Dirbaio - Creator of the NSMBDS asm patch template which was used as a basis.
• StapleButter - Partial coding of the Filesystem classes.
• Icons8 - Icons (https://icons8.com).