https://docs.oracle.com/cd/E28853_01/html/E28858/z4001b331399342.html
xhci Device Failed During Boot on USB Ports (15809582) - SPARC T5-2 Server Product Notes
When you boot the Oracle Solaris OS with a USB 3.0 device installed in one of the rear USB ports of a SPARC T5-2 server, the following message might be...