Q: after downloading ios 8.2 my screen has gone black.

Hey  K_Gull,

Here are some steps to try if your iPhone is working, but the display is black.

If your iPhone, iPad, or iPod touch doesn't respond or doesn't turn on - Apple Support
https://support.apple.com/en-is/HT201412

 

If you see a black screen

You might need to charge your device before it can turn on. Plug in your device and let it charge for at least 10 minutes (20 minutes for iPad), then try turning it on. 

You should see a battery icon while your device is charging. If you continue to see a black screen, reset your device. 

Restart or reset your iPhone, iPad, or iPod touch - Apple Support
https://support.apple.com/en-is/HT201559

Hope that helps,

- Judy