root@openwrt:~# airmon-ng start phy0-mon0
/usr/sbin/airmon-ng: line 14: mountpoint: not found
/sys is not mounted, you can probably mount it with:
mount -t sysfs sysfs /sys
This program cannot continue without a working sysfs.
root@openwrt:~# mount -t sysfs sysfs /sys
mount: mounting sysfs on /sys failed: Resource busy