Yet Another BootImage Tool (yabit)

yabit is a python written, device tree-aware tool to create, extract and update Android BootImages ("boot.img"). It depends only on a reasonably up-to-date Python interpreter (3.4+) and the standard library.

Usage

usage: yabit.py [-h] [--debug] [--input INPUT] [--output OUTPUT]
				[--dump {nothing,everything,header,kernel,initramfs,dtbs} [{nothing,everything,header,kernel,initramfs,dtbs} ...]]
				[--dump-to DUMP_TO] [--print-header] [--cmdline CMDLINE]
				[--remove-original-dtbs] [--dtb DTB [DTB ...]]
				[--kernel KERNEL] [--initramfs INITRAMFS] [--base BASE]
				[--kernel-offset KERNEL_OFFSET]
				[--initramfs-offset INITRAMFS_OFFSET]
				[--second-offset SECOND_OFFSET] [--tags-offset TAGS_OFFSET]
				[--pagesize {2048,4096,8192,16384}]

optional arguments:
  -h, --help            show this help message and exit
  --debug               enables debug logging
  --input INPUT, -i INPUT
						the input image path
  --output OUTPUT, -o OUTPUT
						the path where to store the output
  --dump {nothing,everything,header,kernel,initramfs,dtbs} [{nothing,everything,header,kernel,initramfs,dtbs} ...], -u {nothing,everything,header,kernel,initramfs,dtbs} [{nothing,everything,header,kernel,initramfs,dtbs} ...]
						what to dump. Might be specified multiple times.
						Defaults to nothing
  --dump-to DUMP_TO, -t DUMP_TO
						where to dump the specified images. Defaults to the
						current directory
  --print-header, -e    prints the header
  --cmdline CMDLINE, -c CMDLINE
						use the supplied cmdline
  --remove-original-dtbs, -r
						removes the original dtbs found in the kernel
  --dtb DTB [DTB ...]   appends the specified dtb to the kernel. It might be
						used multiple times
  --kernel KERNEL       uses the specified kernel image
  --initramfs INITRAMFS
						uses the specified initramfs image
  --base BASE           the base address to use
  --kernel-offset KERNEL_OFFSET
						the kernel offset
  --initramfs-offset INITRAMFS_OFFSET
						the initramfs offset
  --second-offset SECOND_OFFSET
						the second bootloader offset
  --tags-offset TAGS_OFFSET
						the tags offset
  --pagesize {2048,4096,8192,16384}, -p {2048,4096,8192,16384}
						the page size to use

Examples

Replacing the kernel image with another

./yabit.py --input boot.img --kernel bzImage --output boot.img

Extracting every component from an image

./yabit.py --input boot.img --dump everything --dump-to result/

Replacing eventual compiled DeviceTrees (DTBs) with a custom one

./yabit.py --input boot.img --remove-original-dtbs --dtb custom_dtb.dtb --output new_boot.img

The --remove-original-dtbs switch removes eventual DTBs already present in the kernel. The specified DTB is appended afterwards.

Creating a new boot.img

./yabit.py --kernel bzImage --initramfs initramfs.gz --cmdline "lpm_levels.sleep_disabled=1 user_debug=31 androidboot.selinux=permissive msm_rtb.filter=0x3F ehci-hcd.park=3 dwc3.maximum_speed=high dwc3_msm.prop_chg_detect=Y coherent_pool=8M sched_enable_power_aware=1 androidboot.hardware=kugo" --base 0x80000000 --output boot.img

Notes

yabit was written to satisfy a specific need (replacing DeviceTrees on an already made image) and it grew up to become a sort-of swiss army knife for boot images.

There is still some work to do, though, such as support for the second bootloader image, better error-handling and the code is not as well commented as I'd like.

Contributions (including extensive testing) are welcome.