Bootloader overview | Android Open Source Project
Effective in 2026, to align with our trunk stable development model and ensure platform stability for the ecosystem, we will publish source code to AOSP in Q2 and Q4. For building and contributing to AOSP, use android-latest-release. The android-latest-release manifest branch will always reference the most recent release pushed to AOSP. For more information, see Changes to AOSP. A bootloader is a vendor-proprietary image responsible for bringing up the kernel on a device. The bootloader guards the device state and is responsible for initializing the Trusted Execution Environment (TEE) and binding its root of trust. The bootloader also verifies the integrity of the boot and recovery partitions before moving execution to the kernel. Here's an example bootloader flow: Load and initialize memory. Verify the device according to Verified Boot flow. Verify the boot partitions, including boot, dtbo, init_boot, and recovery, according to the Verified Boot flow. As part of this step, check the b