Motherboard replacing from EE to O2

As in topic.

I changed motherboard in my HTC One Mini 2... and rear camera stop to working. Front camera works fine. Originally motherboard and phone was EE, now motherboard is from O2. Because motherboard was O2 I must unlock phone, I did it.

After unlocking rear camera sometimes was working, and on second day after motherboard replacing, completly stops to work.

After motherboard changing everything works fine except rear camera...

Any suggestions...?

Hello,

I fixed problem with silver colored tapes. This is not a solution...

I think back cover cause problems with camera. Nothing else, just back cover. Camera works without back cover! I try find solution.