OH Boy.....I did all the above and all the above in many forums..got Samsung troubleshoot over a chat factory reset 3 times...safe mode...tried all the cashe deletes data deletes ect...so the only thing that I could figure out was under settings...security....clear all certificates was greyed out so I could not do that...then under security ..trusted credentials..display all certificates I find about 100 certificates and have to disable each one...then I did the hold volumn button with power button together and get the black screen to restart the phone...after 2 weeks and hours of frustration I felt like I had my first baby..cause my camera and my flash was WORKING! Oh joy and bliss