How to Brush Ubuntu 16 System on Xavier

I am very lucky to start an Xavier,But when Xavier finishes brushing the system, ubuntu18 is found, and my program can only run on ubuntu16.How does Xavier brush the machine to ubuntu16? Does this affect performance?

Hi 73741837, JetPack 4 supports flashing Ubuntu 18.04 to the target Xavier device, not Ubuntu 16.04.

On the host PC, JetPack can run under Ubuntu 18.04 or 16.04, but it always installs Ubuntu 18.04 to the target Xavier device.

BTW, on a minor note, I think by “brush” you mean the term “flash”.