The 'what' could really be anything since the article is vague, from the sensors themselves to the GNCP software that takes that info and controls the spacecraft. If they were patching the instrument(s) then they could have done anything from uploading a new configuration to memory or the even loading a new FSW build.
Based on the little info in there I'm guessing the LIDAR hardware is their already planned backup system so when the primary sensors didn't function as planned they switched over. In this scenario I'd expect the controllers to want to hold off so they can configure the LIDAR and run its self test procedures as well as configure GNCP and ground control.
