If it can't mine on it, then that would be coz it can't talk to it thus it can't tell it to turn the led off.
It is possible to enable/disable a device using the USB menu. I have sometimes slow nanofurys because of several reasons. To find them I disable and wait. Then I try to find the cold one. If the LED would be switched off, it would be much easier.
actually I think we're talking about two separate features (that are missing in that sense) :
- Identify - the LED can be controlled independently of the device' power; Just flickering the LED would be sufficient for what rgr_rgr wants;
- power-off/on - main "power switch" (if we can call it so) within each NanoFury can also be flipped. This might be helpful when testing for possibly overloaded hub without having to physically remove the device.