TomatoUSB

tomato usb v1.28.8752 ND vpn3.6
Buffalo WHR-HP-G54

When enabling the radio using the "AOSS" pushbutton, the WLAN LED does not always come on immediately.
There is a variable delay before it comes on - may be immediate, may be many seconds.
I believe (not certain) that what makes it come on is when a wireless client sends a response to the access point. The light always comes on, with blinking to indicate traffic of course, once a client has established a link to the access point. Sooner or later this always seems to happen (I am in an urban area with lots of wifi traffic) but in the meantime you don't know whether or not the router has accepted the request to enable the radio.

This behavior is different from regular Tomato and is less useful, because there is no immediate feedback as to whether the radio is enabled or disabled.

The WLAN LED is controlled by the wireless driver, all we can do to affect it is to set various "magic" nvram keys (not documented of course)…

Original Tomato uses different - older - driver - that might explain the difference.
Have you tried one of the recent dd-wrt builds on your router, and if so - did the WLAN LED work correctly in dd-wrt?

You can also try the following (based on dd-wrt code):

nvram set wl0gpio2=136
nvram commit
reboot

Thanks for the info. I didn't know about that nvram variable.

Actually I came up with my own solution, which was to add this code to the "custom script" on the Buttons / LED page.

if [ $1 -ge 4 ] && [ $1 -le 6 ]; then
   radio toggle
   if [ $(( `wl radio` )) == 0 ]; then
     led wlan on
   fi
fi

This unconditionally turns on the LED when the script executes. That would be good enough for me. Experiment shows that the driver takes over the LED when there is traffic, so the LED still blinks despite the "led wlan on" command. If "radio toggle" turns the radio off, the LED is turned off by the driver.

I might try the nvram variable you mentioned over the weekend.