Flash, front and rear camera all not working

The Front Camera and Flash will not work if the Rear Camera is defective/damaged/disconnected so focus your efforts on the rear camera. Start by verifying if it is properly connected. You can also check the condition of the connector (flex and board) as well as the general condition of the flex cable itself and the logic board. The flex is delicate and even the tiniest tear can cause issues. Likewise for the logic board as there are tiny components all around the connector and damaging or dislodging components can happen.

If everything looks okay, you could try to disconnect the FCAM & Flash and see if the Rear camera works by itself. If it doesn’t, then consider replacing the camera.