Hi,
I've added those lines to disable wifi led:
system.led_phy0=led
system.led_phy0.name='PHY0'
system.led_phy0.sysfs='ath9k-phy0'
system.led_phy0.trigger='none'
system.led_phy0.default='0'
on TP-LINK TL-WR741ND v2 led remains on,
cat /sys/class/leds/ath9k-phy0/brightness shows 0
on TP-LINK TL-WR842ND v1 led goes off.
WR741 - 18.06-SNAPSHOT, r7349-70cb2d20c9
WR842 - 18.06-SNAPSHOT, f1a2b5bbbc