Hi,
we could get the controller flashbackup file from #cd /var/airwave/device-backup/ap/<id> directory.
We could get the id of the controller from APs/Device>monitor page URL link
https://<Airwave IP>/ap_monitoring?id=5
Note: In Airwave 8.2.4, we blocked CLI root access and we cannot run any custom script.
Regards,
Pavan