Quick answerA phone update package is only one part of the installation. The operating system needs significant temporary space to decompress files, store a backup of the current system, and prepare the new version. This process ensures the update is stable and the device can recover if something goes wrong, but it demands far more storage than the download size suggests.The update package versus working spaceWhen a phone's operating system (OS) needs an update, the download file size can seem small. For example, an 800MB update is common. However, the phone often reports that it needs 10GB or more of free storage to install this update. This difference comes from how updates are processed on the device itself. The 800MB is the compressed package that arrives over the internet. This file then needs to be unzipped and expanded, which immediately uses more space.Beyond decompressing the update, the phone creates a…