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.
When you attempt to flash the file, the recovery checks the last few bytes of the ZIP (the footer) for specific markers (like 0xff ) and then validates the cryptographic hash against its internal store. How to Use update-signed.zip There are two primary ways to apply these updates manually: 1. Via Local Update (System Settings) update-signed.zip
Many modern Android versions allow you to install a ZIP directly from the menu: Sign builds for release - Android Open Source Project Inside the ZIP, you will typically find a
Understanding update-signed.zip: A Guide to Android OTA Packages Via Local Update (System Settings) Many modern Android
Developers often use the SignApk.jar tool to sign their own custom packages.
For an update to be accepted by a stock recovery, it must pass a "whole-file signature verification".