Hi,
Per checked internally, this is a bug that will be fixed in rel-32.6.1.
If you want to stay on rel-32.5.1, the workaround is
download l4t_payload_updater_t210.py from the NVIDIA Developer web site’s L4T 32.5 Archive to the Linux_for_Tegra directory. Then copy the file to its final location and make it executable:
$ cd Linux_for_Tegra/
$ sudo cp <l4t_payload_updater_t210.py> rootfs/usr/sbin/l4t_payload_updater_t210
$ sudo chmod a+x rootfs/usr/sbin/l4t_payload_updater_t210