Most people should be unaffected by the update, but there are a handful who run Linux on their PS3s, and those folks can opt out of the patch. Unfortunately, doing so will block access to some major features:
- Ability to sign in to PlayStation Network and use network features that require signing in to PlayStation Network, such as online features of PS3 games and chat.
- Playback of PS3 software titles or Blu-ray Disc videos that require PS3 system software version 3.21 or later.
- Playback of copyright-protected videos that are stored on a media server (when DTCP-IP is enabled under Settings).
- Use of new features and improvements that are available on PS3 system software 3.21 or later.
Sony says if you are currently using the feature and plan to update to v3.21, be sure to backup data stored on the drive partition used by the "Other OS" as it will not be accessible after the patch.