unzip -p update.zip META-INF/MANIFEST.MF | grep SHA-256 Compare the hash against the original OEM manifest (rarely public). A mismatch indicates tampering. End of Report

To manually verify a ZIP before flashing:

This report is structured for an IT administrator, advanced user, or developer who needs to understand the constraints of the stock recovery environment and how to properly source and apply update ZIP files. Analysis and Procedure for Android System Recovery 3E Update ZIP Deployment