Where is the debug UART?

Has anyone managed to work out how to hook up a UART for debugging? The K1 chip has four UARTS; I’d expect at least one of them to be brought out somewhere on the motherboard, but I can’t find it.

crwdns2934089:0crwdne2934089:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2889612:0crwdne2889612:0 0
crwdns2934285:0crwdne2934285:0