Hướng dẫn cách hủy update cho IPhone 4

Bác làm theo cách sau để loại bỏ triệt để:

1. First, turn off WiFi! That will PAUSE the update. It will still try to resume unless you do the following

2. Next, ssh in to your iPhone and do: 
cd /var/mobile/Library/SoftwareUpdate
mv softwareupdateservicesd.plist softwareupdateservicesd.plist.bak

3. Go to Settings > General > Reset All Settings
(It's annoying to re-enter your WiFi password and choose your wallpaper, but your mail accounts etc. remain intact). 
Your phone will reboot. 

4. Go to Settings > General > Software Update
it should say "your software is up to date" --> go to step 5. 
if it offers you the new update (but has not started the download) --> you are done! 
if it still shows a paused download, repeat steps 1-3, rebooting after each step. 

5. ssh in to your iPhone and do: 
cd /var/mobile/Library/SoftwareUpdate
mv softwareupdateservicesd.plist softwareupdateservicesd.plist-bak2
mv softwareupdateservicesd.plist.bak softwareupdateservicesd.plist

6. Go to Settings > General > Software Update
it should give you an error. 

7. Navigate back to General, and General > Software Update again
it should offer you the 5.1 update.

Để remove các file download dang dở trong trong quá trình update trên, bạn vào thư mục sau:

/var/mobile/Library/Assets/

Xoá 2 folder:

com_apple_MobileAsset_SoftwareUpdate
com_apple_MobileAsset_SoftwareUpdateDocumentation

Đó là cách mình đã thực hiện. Chúc thành công!