Wait.
Let me get this straight, just so we have it in plain English on the forums.
You attempted to install our FreeBSD-based appliance, FreeNAS, on one of our recommended SuperMicro models, and you had perfectly normal devices, like keyboards, and stuff, plugged in. You received the dreaded
Kernel: KDB: enter
panic message. You have determined that the operating systems boots, 100% of the time, when your USB keyboard is not plugged in, and does not boot, 100% of the time, when it *is* plugged in. Therefore, the presence of the USB keyboard is the problem with the early boot sequence.
This is the statement you are making?
I am not doubting you, I just want to make sure I am following the conversation correctly, and putting it very clearly to those that might come after searching for this kernel panic.
If that is correct, please let us know the exact make and model of the keyboard. If you are inclined to do more experimentation, could you trying plugging the keyboard into other ports? Does it do it only on USB 2.0 ports? Only on 3.0 ports? Only on the one port that you happened ot have it plugged into? Does it do it when it is the ONLY device plugged into USB ports? etc? Can you try it with a different USB keyboard? Can you try it, perhaps, with a wireless mouse or other USB device?
I'd like to diagnose exactly what's causing the problem here to find out if it is an electrical problem, or actually some kind of problem with core BSD functionalities like devd.