Apple's iOS 8.0.1 update is no longer available for download because it disrupted cellular functions and disabled Touch ID on iPhone 6s, meaning those who downloaded the software essentially now have broken devices and must seek a fix on their own.
Apple has confirmed it is working on a fix in the guise of iOS 8.0.2, but in the meantime how do you get back to iOS 8.0 so you can use your phone?
You would typically need to restore your iPhone 6 or 6 Plus in order to get it back up and running like normal, at least until Apple finishes investigating the issue and releases a second update that would not only fix the new probelms but also the first bug that stopped HealthKit-enabled apps from launching in the App Store.
But the good news is you don't have to wipe your iPhone or even wait for Apple.
There is an easy way to get rid of iOS 8.0.1 and all the errors it included. All you need is your iPhone 6 or 6 Plus, a Lighting to USB cable, access to a computer with iTunes installed, and an internet connection. Got those things handy? Well then keep reading to learn more.
How to fix your broken iPhone:
3. Download the latest version of iTunes for Mac or PC from iTunes.com.
4. Use a Lightning to USB cable to connect your iPhone 6 or iPhone 6 Plus to your computer.
5. Open iTunes on your Mac or PC.
6. Once iTunes launches, click "iPhone" in the top-right corner.
7. Click "Check for Update" - while pressing Option (on a Mac) or Control (on a Windows PC).
8. Find and select the iOS 8 firmware file (.ispw) you downloaded earlier. Click "OK" when done.
9. Your iPhone 6 or 6 Plus will then install iOS 8 as an upgrade but without deleting settings or data.
10. Once iOS 8 installs, re-enable Find my iPhone (Settings > iCloud) on your iPhone.
And finally, confirm you're running iOS 8 by checking the About menu on your device. If there is a problem, you might need to do a full restore for your iPhone, which includes putting your iPhone into Recovery mode and then using a backup.
Visit Apple's support page for instructions on how to restore an iOS device from a backup. Alternatively, you could put your iPhone into DFU mode and then restore it. You can read more about how to do that on another support page in Apple's forums.
If none of the above options appeal to you, simply wait for Apple to release a second update. But there's no word yet on when that'll happen.