Share your experience!
Greetings,
My M4's flashlight is not working, I bought the phone from Vodafone Hungary 3 days ago. On the first day, I used it once, but now is dead, even in safe mode. Any suggestions? Oh, and it doesn't work with third party app either.
Hi 
It looks like a hardware defect.
I will give you steps by which you could repair your phone's software to see if it fixes the issue, otherwise you will have to return the handset ( as soon as possible).
Update / Repair your phone via PC Companion
Download PC Companion and install it. Do not connect your phone until you're asked to do so.
Launch PC Companion > Start Support zone > Start Phone/ Tablet Software update > select Repair my Phone / Tablet > Follow the on-screen instructions it shows.
Can you check if the same occurs with a 3rd party app from google play?
What error do you get in the camera?
Settings > apps > all > camera > clear data > restart the phone > boot on safe mode
http://talk.sonymobile.com/t5/FAQ/How-to-boot-your-phone-into-safe-mode/m-p/348008#U348008
Has safe mode made any difference? Do you have OK google enabled?
No the safe mode not made any difference, and for "OK Google" i don't know i don't use it. Thank you anyway.