Apple today released iOS 10.3.3 to the public. iOS 10.3.3 comes more than two months after the launch of iOS 10.3.2, a minor bug fix update.

Step 1: Update to the latest version of 3uTools and then backup your iDevice as the before tutorial.  Connect your iDevice to your PC with  authentic USB cable, and then go to "Flash & JB" -> "Easy Flash". 

Step 2: Select the iOS 10.3.3 firmware and then click "Flash". Before flashing, select the option "Retain User's Data While Flashing" if you want to save your data.

Step 3: Keep a good connection between your iDevice and your PC and wait for several minutes till the process is finished.