Apple has pulled back an update to its new operating system and offered a guide to revert to iOS 8 after many iPhone 6 and 6 Plus users complained about a drop in mobile service and inability to use the fingerprint-reading Touch ID.
The company also said it would release iOS 8.0.2 in the next few days to fix the issue with iOS 8.0.1.
The record-selling new phones have already faced criticism over their bendability, dubbed "bendgate" on social media.
Some users also complained of "sluggish wi-fi and dwindling battery life" after updating to iOS 8 on Twitter and Apple forums, Time magazine reported earlier this week.
Apple, which started selling the new phones last Friday, issued a step-by-step guide for users to reinstall iOS 8 through the latest version of iTunes.
Its health app will not work after the reinstallation, but will be fixed in iOS 8.0.2, said the company, which has not commented on the bending-phone reports.
Social media and online forums have been full of comments about how the new phones can bend when placed in back pockets or while wearing skinny jeans.
The phone's lightweight aluminium shell is more malleable than expected, but this may not qualify as a design flaw, some analysts said.
Rival smartphone makers have tried to take advantage of Apple's problems.
Samsung released an ad showcasing a bending phone against its own product, while Blackberry's chief executive John Chen said: "I would challenge you guys to bend our Passport."
On Monday, Apple said it had shipped 10 million units of the iPhone 6 and 6 Plus since it began selling the phone on Friday.
