I have iPhone 4S iOS 9.3.6, iPhone 6 12.4.6, iPhone SE iOS 13.4.1, iPhone 8 iOS 13.4.1 and an iPad Pro iPadOS 13.4.1. Prior to that I had iPhone 3GS which is not working any more.
I have been updating all these devices whenever a new iOS is released. I have never encountered any issue whatsoever after any update because I have never downloaded anything over internet directly. Always used apps from App Store only.
Hence I am sure iOS update is not the cause of your iPhone's issue.
- You still see a black screen after charging, force restarting, following the steps in this article.
- You see a black screen, but you can hear alerts, sounds, and vibrations.
- The screen remains black, but the device chirps when you unmute it and connect it to power.
- Your screen is on, but it doesn't respond when you tap, slide, or try other gestures.
- You can't force your device to restart because a button is broken or stuck.
- Your device is stuck on the Apple logo, displays a solid color, or isn't recognized in iTunes.
Contact Apple Support to set up service if you have any of the above issues: