An unidentified bug in Apple's iOS 10 upgrade bricked users' devices this morning, requiring manual restoration.
The general availability of iOS 10 followed a beta preview program that Apple kicked off in July this year. The update arrived this morning Australian time.
Some users immediately reported problems with the update to iOS 10, which rendered their phones unbootable.
iOS 10 update temporarily bricked my iPhone 6s Plus ... so yeah, I'd hold off on that. pic.twitter.com/qPFU1bpqZs— Marques Brownlee (@MKBHD) September 13, 2016
Apple confirmed the problem said it had been resolved.
"We experienced a brief issue with the software update process, affecting a small number of users during the first hour of availability," an Apple spokesperson said.
"The problem was quickly resolved and we apologise to those customers. Anyone who was affected should connect to iTunes to complete the update or contact AppleCare for help.”
iOS 10.0.1 contains a fix for the bricking issue, Apple said.
The new mobile operating system brings new features for users, opens up built-in system apps to third-party developers, and contains several important security fixes for iPhones, iPads and iPods, Apple said.
Two fixes to iOS sandboxing and the GeoServices feature prevent malicious applications from accessing unauthorised information like a text recipient and the device location.
Apple also plugged a bug that meant user communications for iOS updates was not properly secured with the encrypted HTTPS protocol. That flaw could be abused by an attacker in a privileged network position to stop devices from receiving updates.
Earlier versions of iOS also did not handle untrusted digital certificates properly, a flaw that could be exploited by attackers in a man-in-the-middle network position to intercept iOS Mail user credentials.
The Handoff feature for the Messages app in iOS 10 has been patched to prevent texts from becoming visible to other devices not signed into Messages. Similarly, the iOS Keyboard was inadvertently caching sensitive information, which can be revealed through auto-correct suggestions.
The above fixes apply to the iPhone 5, iPad 4, and iPod touch 6 models.