iPhone 6s plus both cameras not working.

It seems strange that the earpiece speaker and both cameras are not working.

You can start by.

·         Checking the rear and front camera flexes are seated properly.

·         Disconnecting the front camera flex and see if rear camera will work.

·         Disconnecting the rear camera flex and see if front camera works.

·         Check both the connectors under some sort of magnification for damage.

·         Replace the front camera flex assembly.

·         Replace rear camera

As I said it seems strange you have three things going on. If it was just the front camera and ear speaker that would point to a faulty flex assembly or FPC connector. But I think the rear camera should still work.

Other than the above suggestions there is not much more you could do if you haven’t got the proper knowledge and equipment.