引自：http://lifehacker.com/how-to-upgrade-to-ios-7-right-now-1288208215

 

Although iOS 7 won't see an official release until September 18th, you can install the final version right now even if you're not a developer thanks to some anonymous public postings of the software update files.P

Note: We updated a few iDevices using these files and encountered no issues, but because we're unable to verify every single one we can't say for certain that problems won't arise. This is the GM release—the same one that will get released to the world next week—so it should work just the same, but there's always a chance you could run into an issue. Please be aware that there's some risk involved before you upgrade.P

Back Up First!P

Before you do anything, back up your iDevice with iTunes. In the past, we've rarely seen an issue with early upgrades but that doesn't mean issues don't happen. You may need to restore your device, so back it up first!P

Download iOS 7P

Thanks to a public (and probably temporary) posting on Mega, a number of iOS 7 updates are available for download. Not all devices were posted, but if more show up we'll add them. Here's what's available so far:P

Note: iOS 7 requires a later version of iTunes so you may not be able to use your iDevice with iTunes post-update (at least, not until Apple releases the new version or you install the beta).P

Install the UpdateP

To install iOS 7 on your device, follow these instructions:P

  1. Open up the disk image (.dmg) and find the iPhone Software Update file (.ipsw) for your device. Drag it to the desktop, or a folder of your choosing. (Windows users will need a tool like 7-Zip to do this, and will need to open the .hfs inside the .dmg as well.)
  2. Open iTunes and connect your iPhone, iPad, or iPod touch, to your computer.
  3. If your device isn't automatically selected in iTunes, select it and go to the "Summary" tab.
  4. Hold down the option key (OS X) or the shift key (Windows) and click the Restore button. Browse to the .ipsw file you downloaded, select it, and wait for the update to finish.
  5. If necessary, restore your device from backup and sync with iTunes.

That's it. If you follow those steps, you'll be up and running iOS 7 in no time.