| Section | Description | |---------|-------------| | | Standard Android boot image header (size, kernel address, ramdisk address, etc.) | | Kernel | Image or zImage – the Linux kernel for Exynos 9810 | | Ramdisk | Gzipped CPIO archive with root filesystem used in early boot | | DTB (Device Tree Blob) | Hardware description for Exynos 9810 (sometimes separate in dtb.img ) | | Samsung Signature | Cryptographic signature (Samsung's signature_blob ) for verified boot |
dd if=/dev/block/by-name/boot of=/sdcard/boot.img On a rooted S9, you can pull it via adb pull /sdcard/boot.img . Use bootimg-tools or magiskboot (from Magisk) to unpack: samsung s9 boot.img
Check partitions on S9:
On the S9, Samsung introduced (security) and AVB (Android Verified Boot 2.0) with dm-verity on the system partition, but boot.img itself is signed with a Samsung OEM key. 2. Location and extraction The boot.img is stored in the boot partition , not inside the super partition (system/vendor). | Section | Description | |---------|-------------| | |
A typical boot.img contains:
Note: The Snapdragon variant (SM-G960U) has a locked bootloader on most models, making boot.img extraction and modification significantly harder. This answer focuses on the Exynos variant, which is developer-friendly. On the Galaxy S9, boot.img is not just a simple Linux kernel + ramdisk archive. Samsung uses the Android Boot Image format but with Samsung-specific headers and signatures . Location and extraction The boot
adb shell su ls -la /dev/block/by-name/ # Output includes: boot, boot_backup, recovery, system, vendor, etc. To dump boot.img :