This is the most common reason. Apple frequently stops "signing" older versions of iOS shortly after a new release. This means you cannot downgrade once Apple stops signing the firmware. However, during the short window (usually a few days or weeks) when an older version is still signed, downloading the specific IPSW file allows you to revert to a more stable or battery-friendly version of iOS.
Let’s walk through the actual process. This assumes you have downloaded your desired .ipsw file to your computer desktop. ipsw download ios
Public betas can be fun, but they can also kill your battery or crash apps. The only safe way to exit a beta without losing data (in most cases) is to download the latest stable IPSW and perform a restore. This is the most common reason
If an Over-the-Air (OTA) update fails, your iPhone might get stuck in a boot loop (the dreaded Apple logo screen) or enter Recovery Mode. iTunes or Finder often fail to fix these issues using the standard update method. Downloading the IPSW file and performing a manual "Restore" often bypasses these glitches and brings the phone back to life. However, during the short window (usually a few