Hello,
I just got my Acer Iconia W4-820-NTL31AA004. Everything was great at first. But after about a day, the front cam no longer works. I can use the back cam, but the front cam only shows a blank screen in any camera app. In the device manager, there is Intel 2400 under imaging devices and OV2722 and 0V5693 under System devices.
What I did was
1) Uninstall default Acer softwares
2) Update Windows
I dont know what caused the camera failure from the above two things I did. I uninstalled as many Windows updates as I could from the ones that I had installed. I can't refresh or reset the device as I dont have an OTG cable or USB CD ROM.