I tried the posted instructions without removing the battery and it did not work. Then I retried and removed the battery for abount 30 seconds - still no joy. So I followed every step as outlined - sucess!! Reinstalled the camera app and still working - so far (time will tell if it sticks)

the reason removing the battery would make a diffrence is that almost all electronics now days does not realy turn off when you power down. the only way to remove low level hardware settings is to compleatly power off the hardware i.e. remove the battery for a time.