What format should the update file be when using ADB?

When using the "Update from ADB" option on an Android device, one of the most important steps is ensuring that the update file is in the correct format. ADB (Android Debug Bridge) is a command-line tool used by developers, technicians, and advanced users to interact with Android devices. One of its functions is to sideload firmware or system updates directly to a phone or tablet. But for this process to work, the update file must meet specific format requirements for update from ADB.

Correct Format: ZIP File

The update file used in an ADB sideload operation must be in a .zip format. This ZIP file is typically referred to as an OTA (Over-The-Air) update package. It contains all the necessary files to update your system, such as new firmware, system apps, security patches, and scripts to install them safely.

However, not all ZIP files are created equal. The file must be signed and structured properlytypically by the device manufacturer or an official Android build environment.

Signed OTA Packages

The update ZIP must be digitally signed to pass Androids recovery verification. Devices running stock Android will reject unsigned or incorrectly signed updates during the installation process. If the signature check fails, you may see an error like "signature verification failed" or "installation aborted."

How to Recognize a Valid ZIP for ADB Sideload

A valid update ZIP for ADB sideload will usually have:

• A name like update.zip, ota-update.zip, or similar

• An internal structure including files like META-INF/, system/, and boot.img

• Compatibility with your specific phone model and Android version

Where to Get ADB-Compatible ZIPs

Update ZIP files can be obtained from:

• The official website of your devices manufacturer (e.g., Google, Samsung, OnePlus)

• OTA update forums or developer communities like XDA Developers (always verify trustworthiness)

• Backup tools that extract OTA packages during regular updates

Avoid downloading update ZIPs from unknown sources, as installing an incorrect or malicious file via ADB could lead to software errors or even a bricked device.

What Not to Use

Do not attempt to sideload the following types of files:

• .img files (boot images or factory images are not compatible with ADB sideload directly)

• .tar or .rar archives

• .apk files (these are app packages, not system updates)

• Unzipped foldersonly compressed, signed ZIP files are valid for the process

How to Use ADB Sideload with a ZIP File

Once you have a valid ZIP file:

1. Place the ZIP in your computers ADB working directory.

2. Boot your phone into Recovery Mode.

3. Select Apply update from ADB.

4. On your computer, use the command:
   adb sideload update.zip

5. The system will verify the file and begin the update process.

Conclusion

To use Update from ADB effectively, the update file must be a signed ZIP package specifically built for your device. Installing any other format will result in errors or failed updates. Always ensure you have the correct firmware from a trusted source and never sideload unverified files. This process is powerful and useful, but it requires caution, precision, and the correct file format to work properly.