Artosyn Firmware Tools

Tools to deal with Artosyn ARTO v4 firmware image files. Inspired by dji-firmware-tools.

Prequisites

Make sure you have nodejs 16 or above and npm installed. You can use nvm to do so.

Installing

git clone https://github.com/fpv-wtf/ar-firmware-tools
cd ar-firmware-tools
npm install

Usage

otra.js <command>

Commands:
otra.js extract <image> [folder]  extract the OTRA image
otra.js info <image>              show info on the OTRA image

Options:
--help     Show help                                 [boolean]
--version  Show version number                       [boolean]

Scripts

In order to make deep extraction of firmware packges easier some helper scripts are included. These scripts target Ubuntu Linux.

First, make sure you install jefferson for exrtacting JFFS2 file systems. Additionally, you'll need a copy of mefisto's ext4 tools in the parent directory of ar-firmware-tools. Finally, install the lz4, cpio and device-tree-compiler packages for Ubuntu.

You can achieve this by running (presuming starting in the ar-firmware-tools folder):

sudo apt update
sudo apt install python3 python3-pip liblzo2-dev cpio device-tree-compiler lz4
git clone https://github.com/sviehb/jefferson.git ../jefferson
cd ../jefferson
sudo python3 -m pip install -r requirements.txt
sudo python3 setup.py install
git clone https://github.com/mefistotelis/ext4 ../ext4
cd ../ar-firmware-tools

Deep Extract Avatar FW

Use scripts/avatar_extract.sh ${otra_image} [target_folder] to deeply extract an Avatar_*.img firwmare update. Eg:

scripts/avatar_extract.sh Avatar_Gnd_23.23.4.img

This will:

• Extract the top level OTRA image
• Extract any child OTRA images (effectively just stripping the OTRA header as they are all simple V1 images)
• Extract the kernel initramfs ("rootfs") out of the kernel image to $target_folder/filesystem
• Extract the JFFS2 or EXT4 userapp partition to $target_folder/filesystem/local
• Convert the dtb to dts (human readable format)

Extract rootfs from lz4 vmlinuz

If you just want to extract an lz4 rootfs out of a self extracint lz4 kernel image (u-boot or vmlinuz) do the following:

scripts/lz4_rootfs_extract.sh vmlinuz rootfs_folder

Format Definition

Defined using Kaitai see otra.ksy. You can use the Kaitai IDE to fill in the blanks or explore files.

To renegerate the javascript bindings:

ksc --target javascript --outdir otra_reader otra.ksy

Replace 'javascript' with your language of choice supported by Kaitai and have fun.