I did the iOS 10 update as soon as it became available in India, which was around 10:30 PM on 13th Sep. Subsequently, I bricked the phone and got the connect to iTunes logo.
Here’s what I had to do to get my phone back:
1. Bricked iPhone 6s Plus by downloading the update within 15 min of its launch.
2. Then I tried to do the Update using iTunes but since iTunes was not updated it kept on dowloading 9.3.5 and giving error.
3. Updated iTunes but then it failed to recognize the iPhone as I am on Win 10 and there is some issue with Windows 10 and iTunes.
4. Googling the error showed that under Windows Device Manager – USB Controllers, Apple driver was not showing.
5. Went to Devices and Printers section and under Unspecified Device I can see my iPhone in Restore mode. Went to hardware settings for it and updated driver by going to the C:\Program Files\Common Files\Apple\Mobile Device Support\Drivers
6. Initially even that gave error. Then removed the icon under Unspecified Devices by right clicking on it and then added it back. Tried again using the manual search and it worked this time.
7. Connected back to iTunes, downloaded the iOS 10 update and did the phone update. Now it is all working and the data is intact.
Hope this will help someone.