中文

Android_boot_image_editor

This tool focuses on editing Android boot.img(also recovery.img, and vbmeta.img).

1. Prerequisite

1.1 Host OS requirement:

Linux or Mac development env. To get the most of the toolkit, following packages are also needed: python, jdk 8+, zlib1g-dev, cpio, device-tree-compiler.

1.2 Target Android requirement:

(1) Target boot.img MUST follows AOSP verified boot flow, either Boot image signature in VBoot 1.0 or AVB HASH footer (a.k.a. AVB) in VBoot 2.0.

Supported images:

Image Type	typical file names
boot images	boot.img, vendor_boot.img
recovery images	recovery.img, recovery-two-step.img
vbmeta images	vbmeta.img, vbmeta_system.img etc.
sparse images	system.img, vendor.img etc.
dtbo images	dtbo.img

(2) These utilities are known to work for Nexus/Pixel boot.img for the following Android releases:

• AOSP master
• Lollipop (5.0) - Android 10

2. Usage

Clone this repo with minimal depth:

git clone https://github.com/cfig/Android_boot_image_editor.git --depth=1

Put your boot.img to current directory, then start gradle 'unpack' task:

cp <original_boot_image> boot.img
./gradlew unpack

Your get the flattened kernel and /root filesystem under ./build/unzip_boot:

build/unzip_boot/
├── boot.json     (boot image info)
├── boot.avb.json (AVB only)
├── kernel
├── second        (2nd bootloader, if exists)
├── dtb           (dtb, if exists)
├── dtbo          (dtbo, if exists)
└── root          (extracted initramfs)

Then you can edit the actual file contents, like rootfs or kernel. Now, pack the boot.img again

./gradlew pack

You get the repacked boot.img at $(CURDIR):

boot.img.signed

Well done you did it! The last step is to add the star to this repo :smile

If you are working with recovery.img

If you are working with recovery.img, the steps are similar:

cp <original_recovery_image> recovery.img
./gradlew unpack
./gradlew pack

And you get recovery.img.signed

usage demo

3. example & test

An example boot.img has been placed at src/test/resources/boot.img, which is extracted from Nexus 5x(code: bullhead) factory images from Google, you can take it as a quick start.

4. boot.img layout

Read layout of Android boot.img and vendor_boot.img.

5. compatible devices

Device Model	Manufacturer	Compatible	Android Version	Note
Pixel 3 (blueline)	Google	Y	Q preview (qpp2.190228.023, 2019)	more ...
Pixel XL (marlin)	HTC	Y	9.0.0 (PPR2.180905.006, Sep 2018)	more ...
K3 (CPH1955)	OPPO	Y for recovery.img N for boot.img	Pie	more
Z18 (NX606J)	ZTE	Y	8.1.0	more...
Nexus 9 (volantis/flounder)	HTC	Y(with some tricks)	7.1.1 (N9F27M, Oct 2017)	tricks
Nexus 5x (bullhead)	LG	Y	6.0.0_r12 (MDA89E)
Moto X (2013) T-Mobile	Motorola	N
X7 (PD1602_A_3.12.8)	VIVO	N	?	Issue 35

6. References

boot_signer https://android.googlesource.com/platform/system/extras

cpio / fs_config https://android.googlesource.com/platform/system/core https://www.kernel.org/doc/Documentation/early-userspace/buffer-format.txt

AVB https://android.googlesource.com/platform/external/avb/

mkbootimg https://android.googlesource.com/platform/system/tools/mkbootimg/+/refs/heads/master/

Android version list https://source.android.com/source/build-numbers.html

kernel info extractor https://android.googlesource.com/platform/build/+/refs/heads/master/tools/extract_kernel.py

mkdtboimg https://android.googlesource.com/platform/system/libufdt/

libsparse https://android.googlesource.com/platform/system/core/+/refs/heads/master/libsparse/

Android Nexus/Pixle factory images https://developers.google.cn/android/images