https://openwrt.org/docs/guide-user/storage/usb-drives-quickstart
opkg update
opkg install kmod-usb-storage kmod-fs-ext4 fdisk e2fsprogs
opkg install rsync
# deinstall
opkg remove ppp-mod-pppoe ppp kmod-pppoe kmod-pppox kmod-ppp
# OPTIONAL: remove webinterface
opkg remove "luci-*" #run multiple times
opkg remove uhttpd