So Solaris 11.1 is supposed to support USB 3.0 and I think that may have something to do with it. I have two Gigaware 16GB USB thumb drives that work fine with 11.0 FCS but one of them fails under 11.1. Also not recognized but on occasion I can get /var/adm/messages to log something although most times it has nothing.
So I used a Windows utility to look at both of them and one of them has an older firmware version than the other. The older one doesn't work with 11.1 but the one with the newer firmware runs just fine. Made a nice excuse to upgrade one of them to 32 GB's.