OpenWrt's wifi-scripts validator rejects any macfilter value other than
"allow"/"deny" outright — confirmed on real hardware, setting
macfilter='disable' puts netifd in a permanent restart crash loop with the
radio stuck down. The only way to disable filtering is to delete the option
entirely. Also guards against pushing an empty whitelist (macfilter='allow'
with zero MACs blocks every client outright) by treating it as equivalent
to "off".
Christian Manivong
6b78ebcacb