Yubico Forum

I have a brand new YK4nano and the only configuration I have done was configuring slot 2 for HMAC-SHA1 challenge-response as layed out in MacOSXLogin PDF guide. My key blinks once about every 2-3 seconds ... the manual says that this mean it's not configured? But it is!!!

Even though, using it to login to my Mac works fine, and also OTP (the default slot 1 from factory) works fine.

In the personalization tool in OSX under settings, when I click invert LED behavior, it says settings were saved. But it keeps blinking the same rate. I would assume that inverting it would mean it's constantly on, and blinks off every 2-3 seconds. I have tried unplugging and replugging in the key, but it still blinks the same.

Either way, can I just turn the LED off somehow? It's quite annoying .

Starting with 4.3.1, the LED turns off automatically after 15 seconds of inactivity. There is no invert LED option for the YubiKey 4. The only way to stop the blinking every 2-3 seconds would be to disable CCID mode with the YubiKey NEO Manager (of course this would disable the PIV, OpenPGP, and Yubico Authenticator functions as well).

Hi Chris, thanks for your response. What constitutes "inactivity"? I checked the FW on my YK4nano and it is 4.3.1, however I don't see the LED turning off after 15 seconds of inactivity (not touching keyboard or mouse).

I just installed Yubikey NEO manager and after rebooting (made no changes to the yubikey), now the LED behavior is inverted?!?! Now it's mostly on, and blinks off every 2-3 seconds?? I'm really confused

Unplugged it, then plugged it back in, and now it's inverted again ... off mostly, and blinks on every 2-3 seconds.

The 4.3.1 LED behavior should be as follows:

- Plug in, quick flash (maybe a little longer, depending on how long it takes for the correct drivers to load)
- solid LED for a moment
- off, with flash every ~ 2.5 seconds
- 15 seconds after the step above, LED goes completely dark (I'm using a couple of 4.3.1 YubiKey 4 and that's what they both do)

The "inactivity" is CCID inactivity (that is to say, Yubico Authenticator isn't open, gpg-agent isn't accessing the YK4, and a PIV operation isn't being performed). If you tap the button to send an OTP while it's dark, it will go solid briefly and then dark again.

Regarding your last post, I have no idea, sorry. I've tried inverting and standard LED options in the Personalization Tool on every firmware release since 4.2.6 and it hasn't made any changes.

Hi Chris, thanks for your response.

When I was in my office, I had my macbook with lid closed, and hooked up to an external keyboard and an external display and the LED never stopped blinking.

Once I was packing up to go home and I disconnected the charger, the external display and external keyboard, I noticed after 15 sec the YK did go dark.

It seems like in order for the YK to go dark, the macbook has to enter lid sleep (lid closed + no external displays). That must mean some CCID activity is going on?

Note: I don't have yubico authenticator installed or PIV or gpg or anything using the YK, it is simply plugged in. I have gpg-agent installed but have never set up gpg/ssh with my YK