firmtool

A tool to parse, extract, and build 3DS firmware files.

Compatible with Python >= 3.2 and Python >= 2.7.

Installation

On Windows, install Python >= 3.4 using the installer provided by the official Python website. Make sure that pip is in PATH.

On *ix, install the corresponding packages, they should be named python, python-setuptools, python-pip or similar. You may need to upgrade pip.

The preferred way to install and update firmtool is to run pip install -U git+https://github.com/TuxSH/firmtool.git directly (with the appropriate permissions), although python setup.py install should work as well.

firmtool depends on pycryptodome (either as Crypto or Cryptodome), old pycrypto will not work.

Usage

Showing information about a firmware binary:

firmtool parse the.firm

Extracting a firmware binary, with decryption of the arm9bin and extraction of the k11 modules as well as Process9 (by default type nand-retail is assumed, if it's not the case use -t):

firmtool extract -m native.firm

Same as above plus using ctrtool and the shell to extract the code of each module

#!/bin/bash

firmtool extract -m native.firm
cd modules
for f in *.cxi
do
ctrtool -p --exefs=exefs.bin $f

if [ $f = "Process9.cxi" ]
then
ctrtool -t exefs --exefsdir=exefs exefs.bin > /dev/null
else
ctrtool -t exefs --exefsdir=exefs --decompresscode exefs.bin > /dev/null
fi

cp exefs/code.bin $(basename -s .cxi $f).bin
rm -rf exefs
done
cd ..

Building a firmware binary (for example with two sections, an Arm9 and and Arm11 one, with the entrypoints at the start of the respective sections):

firmtool build test.firm -n 0x08006800 -e 0x1FF80000 -D arm9.bin arm11.bin -A 0x08006800 0x1FF80000 -C NDMA XDMA

Building a firmware binary from an arm9loaderhax.bin payload which doesn't use the Arm11, with a loader supporting the Arm11 entrypoint being 0:

firmtool build test.firm -n 0x23F00000 -e 0 -D arm9loaderhax.bin -A 0x23F00000 -C NDMA

You may also use ELF files, in this case the entrypoint for the given processor is deduced automatically, when applicable (using the first NDMA FIRM section for arm9, and the first XDMA FIRM section for arm11), as well as the addresses of such FIRM sections (using the first loadable ELF sections, and assuming contiguity).