I find that the Xenium LED (the one on the Xenium) goes Red, then Amber, then to off if you boot to XOS or to your BIOS colour if you boot a BIOS (ie Blue, Red, or whatever you set)
BUT my Xternal LED goes Red, then Green, then BIOS colour... I think this is because I have the dimmer set to on, you can actually see a little bit of the red LED when the green one is on, but its not bright at all.
I'm guessing the problem is that amber looks like green on the XLED when the dimmer is set on.
That's okay, red->green->bios suits me

(I have blue, red and green bioses)