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83 lines
2.8 KiB
Markdown
83 lines
2.8 KiB
Markdown
# Android_boot_image_editor
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[](https://travis-ci.org/cfig/Android_boot_image_editor)
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[](http://www.apache.org/licenses/LICENSE-2.0.html)
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This tool focuses on editing Android boot.img(also recovery.img, recovery-two-step.img and vbmeta.img).
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## Prerequisite
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#### Host OS requirement:
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Linux or Mac.
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Also need python 2.x(required by avbtool) and java 8.
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#### Target Android requirement:
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(1) Target boot.img(or recovery.img / recovery-two-step.img) MUST follows AOSP verified boot flow, either [Boot image signature](https://source.android.com/security/verifiedboot/verified-boot#signature_format) in VBoot 1.0 or [AVB HASH footer](https://android.googlesource.com/platform/external/avb/+/master/README.md#The-VBMeta-struct) in VBoot 2.0.
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(2) These utilities are known to work for Nexus/Pixel (or Pixel compatible) boot.img(or recovery.img/recovery-two-step.img) for the following Android releases:
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- AOSP master
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- Lollipop (API Level 21,22) - Oreo (API Level 26,27)
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You can get a full [Android version list](https://source.android.com/source/build-numbers.html) here.
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## Usage
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Get tools via git:
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git clone https://github.com/cfig/Android_boot_image_editor.git
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cd Android_boot_image_editor
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Then put your boot.img at **$(CURDIR)/boot.img**, then start gradle 'unpack' task:
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cp <original_boot_image> boot.img
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./gradlew unpack
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Your get the flattened kernel and /root filesystem under **$(CURDIR)/build/unzip\_boot**:
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build/unzip_boot/
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├── boot.img.avb.json (AVB only)
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├── bootimg.json (boot image info)
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├── kernel
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├── second (2nd bootloader, if exists)
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└── root
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Then you can edit the actual file contents, like rootfs or kernel.
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Now, pack the boot.img again
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./gradlew pack
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You get the repacked boot.img at $(CURDIR):
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boot.img.signed
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#### If you are working with recovery.img
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If you are working with recovery.img, the steps are similar:
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cp <original_recovery_image> recovery.img
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./gradlew unpack
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./gradlew pack
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And you get recovery.img.signed
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## example & test
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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](https://dl.google.com/dl/android/aosp/bullhead-mda89e-factory-29247942.tgz), you can take it as a quick start.
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## boot.img layout
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Read [layout](README.expert.md) of Android boot.img.
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We now support both VB 1.0 and AVB 2.0 layouts.
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## References
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boot\_signer
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https://android.googlesource.com/platform/system/extras
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bouncycastle
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https://android.googlesource.com/platform/external/bouncycastle
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cpio / fs\_config
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https://android.googlesource.com/platform/system/core
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AVB
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https://android.googlesource.com/platform/external/avb/
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