1_unpack_firmware.sh

#!/bin/bash

# create enviroment
rm -r working_dir
mkdir working_dir

extract_part() {
        echo -e "\nExtract $2 from $1 (offset $3, size $4)"
        dd if=$1 of=$2 bs=1 skip=$(($3)) count=$(($4))
}

extract_part "firmware.bin" "working_dir/u-boot.bin" 0 0x50000
extract_part "firmware.bin" "working_dir/uimage.bin" 0x50000 0x50040
# need to know full file size: 'wc -c < FILENAME' -> 0x400000
extract_part "firmware.bin" "working_dir/main_container.lzma" 0x50040 4194304-0x50040

# extract compressed main_container
lzma -d < working_dir/main_container.lzma > working_dir/main_container_extracted.bin

# divide main_container into parts
extract_part "working_dir/main_container_extracted.bin" "working_dir/main_container_header.bin" 0 0x47A000
extract_part "working_dir/main_container_extracted.bin" "working_dir/main_container_filesystem.xz" 0x47A000 2122764 # value found manually by removing byte after byte till getting no error from 7z

# decompress root of main_container
cd working_dir/
7z e -y main_container_filesystem.xz
cd ..

# unpack root CPIO
rm -r extracted_root
mkdir extracted_root
cd extracted_root
cpio --extract --make-directories --preserve-modification-time --no-absolute-filenames < ../working_dir/main_container_filesystem
#cpio --extract --make-directories --pass-through --preserve-modification-time --no-absolute-filenames < ../working_dir/main_container_filesystem
cd ..