Installing SF45 LiDAR on PX4 Without Removing Custom Firmware

I have a PX4-based drone running custom firmware with an older PX4 version. I want to integrate the Lightware SF45/B LiDAR sensor without removing or replacing my existing custom firmware.

Could you please guide me on how to install the necessary LiDAR driver and configure it while keeping my current firmware intact? Any documentation or steps would be greatly appreciated.
@rroche

This isn’t something we support, if you want the latest and greatest PX4 you need to update. When you decide to run an older version of PX4 you need to understand that you are now having to support this version on your own. I suggest you look into how much PX4 has changed from your downstream fork to the latest stable that contains the drivers you need and verify if you are using any interfaces that were either updated or removed in the latest stable, perhaps updating is possible and not a huge problem.