将iOS 5.1降级到iOS 5

Question

我是一个开发人员，我对iOS 5.1升级有一点问题。

所以现在，我想要“降级”iOS 5.1。我已经下载了iOS 5（9a334），然后尝试通过Xcode降级，将文件拖动到Xcode并恢复iPad，但它不起作用。

任何想法？

Answer 1

Downgrades are normally not supported by Apple.

You can try to put your iPhone into recovery mode to restore to the older firmware.

Here are the instructions from Apple:

http://support.apple.com/kb/HT1808

As soon as your iTunes recognizes the iPhone to be in recovery mode, hold the ALT-Key and click on the restore button. It will prompt you to select the firmware you want to restore.

Answer 2

Try this:

1. Plug your device into the PC.
2. While turned on, press and hold both power and home button for 10 seconds.
3. Release the power button after 10 seconds without releasing the home button and hold it until you see iTunes detecting your device in "recovery mode". Your device's screen should be completely black.
4. Press and hold shift if in Windows or Option if in Mac, and then click on "Restore" from iTunes
5. Browse for the desired firmware, and iTunes will start the restoration.