_best_: Update-signed.zip

Yet, the true sophistication lies in the prefix signed- . A digital signature transforms a mundane archive into a verifiable artifact of trust. Using asymmetric cryptography, the software vendor generates a cryptographic hash of the ZIP’s contents and encrypts that hash with their private key. The resulting signature is bundled with the archive. When a client device receives update-signed.zip , it uses the vendor’s public key (hardcoded into the device’s firmware or operating system) to decrypt the hash and compare it against a freshly computed hash of the downloaded file. If they match, two profound truths emerge: first, the update indeed originated from the legitimate vendor (authentication); second, the archive has not been altered, not even by a single bit, during transit (integrity).

Instead of waiting for the automatic notification, advanced users download the OTA update-signed.zip from a mirror or Google’s servers. They then sideload it via ADB in stock recovery. update-signed.zip

: The actual files (e.g., system images, apps, or binaries) being updated on the device. Google Groups How to Generate a Signed Update Yet, the true sophistication lies in the prefix signed-

: The recovery wipes temporary caches (Dalvik/ART cache) to ensure the new software runs smoothly upon reboot. Conclusion update-signed.zip The resulting signature is bundled with the archive

This is a simple script language (Edify) that tells the recovery what to do. Example: