You can monitor the progress in the top bar on iTunes screen.

iTunes will now start the update process by first extracting the Restore Image file.

You’ll get a prompt on PC “iTunes will update your iPhone to iOS 11.4.”, hit the Update button to continue.

Select the Restore Image file (.ipsw) you downloaded in Step 3 above.

└ If you’re on Mac, press and hold the Options key and click on the Update button in iTunes.

Once your device is shown on the iTunes screen, press & hold the SHIFT key and click the Check for Update button in iTunes to select the Restore Image file.

Also, when iTunes greets you with a Welcome to Your New iPhone screen, select Set up as new iPhone and click on the Continue button. If you’re connecting your iPhone/iPad first time with iTunes, you’ll get a “Do you want to allow this computer.” pop-up on screen, select Continue.If a Trust This Computer pop-up shows on your device’ screen, make sure to click on Trust.Connect your iPhone/iPad to the PC using the original USB cable that came with your device.Open iTunes on your Mac or Windows PC.Download iOS 11.4 ipsw firmware file from the downloads section above.How to install iOS 11.4 IPSW file using iTunes iPad (5th generation), iPad (6th generation).iPad Pro (10.5-inch), iPad Pro (12.9-inch, 2nd generation).However, if you’re someone like us who rather prefers to update their iPhone with iOS 11.4 IPSW file via iTunes, below are iOS 11.4 download links for all supported iPhone and iPad models. You can download iOS 11.4 OTA update by going to your device Settings » General » Software Update section. The last beta release for iOS 11.4 was released two weeks ago and now the update is available for download for all iPhone models supporting iOS 11. Apple has finally released the iOS 11.4 update today which has been under testing for the past couple of months.

Iphone 6s firmware