[time-nuts] Undocumented Thunderbolt packet ?

[John L DuBois]

In the process of writing and testing some code to read the Thunderbolt 
TSIP protocol, I have come across what appears to be an undocumented 
reply packet. It is: 0x13 0xNN. (ID = 0x13 and one byte in the packet 
body.) It seems like this is returned when the user has sent command 
packet 0xNN and made some kind of error in the rest of the command 
packet, such as not including required data bytes.

Has anyone else seen this?