Please contact your dealer/workshop, they can use the Niu diagnostic equipment to set the desired unit.
My advice is to inform Niu, that the current OTA has a bug.
Several Ngt owners report a poor GPS reception signal, after updating to version NXA01B11.
Try disconnecting & connecting both batteries, for some this was the solution.
Or try Questions@niu.com, but please post here on the forum to share your experiences and solutions with us.