Replaced Rear Camera, Now Only Shows Black Screen/No Flash

My 6s+ was plagued with the shaky tracking issue everyone else has.

I bought a replacement and installed it. Now flash/led does not work and the camera is not recognized by any app. (Black screen). I reopened the phone and reinserted the OEM one… same issue. All connections are tight and everything is replaced as it should be.

I’ve reseated the ribbons 10 times (which each camera, old and new) and restored my phone to factory. No change.

Did I damage the board? I’ve seen a ton of these questions asked but the answers are always “reboot the phone” “reseat the cables”. That’s not the answer here.

What’s my next move?