Q: disable flash and rear camera

Hi

First follow the instructions here:

• Get help with the camera on your iPhone, iPad, or iPod touch - Apple Support

If the issue persists, contact Apple Support (mail-in service may be available) or make a Genius Bar reservation to arrange for your iPhone to be inspected and, if recommended by Apple, serviced (whether under warranty or via chargeable repair service): 

• Contact - Official Apple Support
• https://twitter.com/applesupport
• http://www.apple.com/retail/geniusbar/