Raspberry Pi CSI cameras not available after installing TBS driver

[mareksaw-cg]

I have recently built a system with a Pi 5 and TBS-5520SE tuner. In this case driver installation went OK and tuner works fine. But then I wanted to add a CSI camera to this system. It does not work. Libcamera-hello says no cameras available. Cameras, flex cables and connections were checked and are OK.

It seems that modifying kernel according to TBS instructions removes CSI camera support. What can be done to solve this issue?