How to decrypt and change the Cook Key in Ubuntu 14.04

1) Dump Cook Key to image file (device sr0 could be different on your system, it should be the device of the Cook Key USB Pendrive):
sudo dd if=/dev/sr0 of=image.img bs=1M

2) Make a backup of the Cook Key image:
cp image.img backup.img

2a) Compress the backup image to ~10MB:
7z a -t7z -m0=lzma2 -mx=9 -aoa -mfb=64 -md=32m -ms=on backup.7z backup.img

3) Insert Ikaro's key and the path to kernel dump file in calc key calc_key.py phython script (https://pastebin.com/EzVu3yH0) and run:
python calc_key.py

4) Compile the crypto-losetup (https://www.mikrocontroller.net/topic/thermomix-rezeptchips#5637422) and use the calculated key to decrypt the image from the Cook Key:
sudo modprobe cryptoloop
gcc -o crypto-losetup crypto-losetup.c
sudo ./crypto-losetup /dev/loop0 path/to/img {calculated key}
mkdir mnt enc_dump
sudo mount /dev/loop0 mnt
sudo cp -r mnt/* enc_dump/

5) Change the files in 'enc_dump' folder with new recipes, images, etc.

6) Create new squashfs filesystem and write to the image.img file:
mksquashfs enc_dump edit.img -comp lzo
sudo dd if=edit.img of=/dev/loop0 bs=1M
sudo umount mnt
sudo losetup -d /dev/loop0

7) Write image.img back to the Cook Key or USB Pendrive that can be read by the machine
sudo dd if=image.img of=/dev/sr0 bs=1M

8) Change serial of the USB Pendrive to: "0 0;exit 0" (without quotes)