This is a tool that signs recovery and boot images for Little Kernel bootloaders affected by CVE-2014-0973.

cuber has been tested working for 3rd-generation Kindle Fire HDX tablets with firmware versions older than 14/13.3.2.4. Most likely affects many other devices using Little Kernel bootloaders built prior to June 13, 2014.

• gcc
• libmpc-dev
• libmpfr-dev
• libgmp3-dev
• libssl-dev
• python
• python-dev
• python-pip

...and python package gmpy2 which can be installed with pip:

$ pip install gmpy2

After ensuring you have all the above packages installed, download the source and compile.

$ wget https://github.com/Verteo/Cuber/archive/master.zip
$ unzip master.zip
$ cd Cuber-master
$ make

$ ./cuber --check /path/to/file.img

Checks if image would pass signature verification.
You may also use -c in place of --check.

$ ./cuber --sign /path/to/input/file.img /path/to/output/file.img

Creates a signature and outputs a signed image.
You may also use -s in place of --sign.