Although many people are benefitting from today's Preview for Developers OS update for Windows Phone 8.1.1, not everyone is pleased. Reports from users with Samsung ATIV devices suggest that today's update is causing endless reboot loops to occur, with hard resetting the device via a key combo not helping.
At this time, it is not clear which ATIV S phones are affected, though Windows Central has had numerous complaints posted in comments.
For now, we advise all Samsung ATIV S users to avoid today's update. Users are advised to head into our Samsung forums, where more details are likely to be posted.