"I tried to upgrade my iPhone 6 plus from iOS 9.3.1 to iOS 10.2 through iTunes, but my iPhone stuck in Apple logo screen when upgrading. What's on the screen of the cell now is the Apple icon and a process bar below with about 3% finished. The iTunes works fine, showing 'updating iPhone software' and the process is stuck at about 30%. So how can I do to get iPhone 6 out of apple screen after updating to iOS 10.2? Please help."
In fact, what you need is just an iOS recovery program like iOS System Recovery. With the help of this program, you can one click to fix your iPhone as well as iPad and iPod touch which stucking on recovery mode, Apple logo screen, DFU mode, white screen, blank screen and other system issues.
Step 1. Install and run the program, and choose the repair iOS system feature.
Step 2. Download and select firmware for your iPhone 6 or iPhone 6s.
Step 3. Fix your iOS to return it to normal.