Answer to "How to Replace Rear Camera Module?"Hi Roman, when you replaced the camera did you receive a 'duo camera is blocked' message? As I replaced the screen on my M8 and get this message now. Apparently the duo camera needs to be calibrated once it gets disconnected from the motherboard or top board and this can only be done using HTC software. Update (01/11/2016): Sadly I didn't manage to sort this, suppose just have to love with it.