Why does my cellphone keep saying that estimating time remaining when I try to upgrade the system?

Question

Why does my cellphone keep saying that "estimating time remaining" when I try to upgrade the system?
Is there anyway to fix this situation?

Answer 1

Hi Eric_Sun,
Thanks for visiting Apple Support Communities.
You may want to update your iPhone using iTunes on a computer if your device only shows "estimating time remaining" when you try to update wirelessly:
If you can’t update wirelessly, or if you want to update with iTunes, follow these steps:
If you use your device's Personal Hotspot for your computer's Internet connection, update your device wirelessly or connect your computer to another network.
Install the latest version of iTunes on your computer.
Plug in your device to your computer.
In iTunes, select your device.
In the Summary pane, click Check for Update.
Click Download and Update.
If you see an error message while updating your device, you can learn how to resolve iOS update errors in iTunes.
You can find these steps here:
Update your iPhone, iPad, or iPod touch
http://support.apple.com/kb/ht4623
If you are still not able to update, I recommend the steps in this article next:
If you can't update or restore your iOS device
http://support.apple.com/kb/ht1808
Best Regards,
Jeremy