Boot.img.lz4 Jun 2026

using mkbootimg :

| Section | Purpose | |---------|---------| | (1–4 KB) | Magic ( ANDROID! ), kernel size, ramdisk size, pagesize, cmdline, etc. | | Kernel (zImage or Image.gz) | Linux kernel for Android | | Ramdisk (CPIO archive) | Root filesystem with init , init.rc , fstab , vendor overlays | | DTB / DTBO | Device Tree Blob(s) for hardware description | | Recoison (optional) | Recovery image components in some A/B slot setups | boot.img.lz4

A standard boot.img can contain an LZ4-compressed kernel (e.g., Image.lz4 ). In this case, the file extension is .img , but inside, the kernel is LZ4. This is common in custom kernels (like NetHunter or ElementalX). using mkbootimg : | Section | Purpose |

During the boot process, the Android device's bootloader (e.g., GRUB, U-Boot) loads the boot.img.lz4 file into memory. The bootloader then decompresses the file using the LZ4 algorithm and loads the kernel and initramfs into memory. The kernel then takes control of the boot process, initializing the device's hardware and loading the main file system. In this case, the file extension is