Inside the ZIP, you will typically find a META-INF folder containing the update script and the signature, and various system images (like system.img or boot.img ) or file diffs.
Developers often use the SignApk.jar tool to sign their own custom packages. update-signed.zip
The term "signed" indicates that the package has been processed with a private key—usually by the Original Equipment Manufacturer (OEM) like Samsung or Google. This allows the device's Stock Recovery to confirm that the update is official and hasn't been tampered with by a third party. How the Signing Process Works Inside the ZIP, you will typically find a
For an update to be accepted by a stock recovery, it must pass a "whole-file signature verification". This allows the device's Stock Recovery to confirm
Manufacturers use a private key to sign the build and include a corresponding public key in the device's recovery partition.
To generate a release image, use: make dist sign_target_files_apks \ -o \ # explained in the next section --default_key_mappings ~ Android Open Source Project