Ah. I guess I've only been logging into the diags system. I'm not entirely sure how to SSH into the main system. Something with USBNetworking and searching for ";Debug" perhaps? Maybe someone can lead me in the right direction?
Anyway, when I noticed /etc/crontab was missing, I created it, and then created /etc/crontab/root with the line I wanted. The following at least confirms that was successful. But again, I guess I only did that in the diags system, so it didn't help me any.
Code:
login as: root
root@192.168.15.244's password:
#################################################
# N O T I C E * N O T I C E * N O T I C E #
#################################################
Rootfs is mounted read-only. Invoke mntroot rw to
switch back to a writable rootfs.
#################################################
[root@[192_168_15_244] root]# cat /etc/crontab/root
*/5 * * * * /mnt/us/weather/display-weather.sh
[root@[192_168_15_244] root]#