We also received a C220 with only one MRAID controller.  I can make virtual disks with that controller, but it has four 500GB SSDs and four 1TB HDDs.  Neither of those seem appropriate for installing ESX.

In case anyone still finds this thread for the answer:Updating the catalog as described here (Cisco UCS Manager Firmware Management Using the CLI, Release 3.1 - Manage the Capability Catalog in Cisco UCS Manager …)And then re-acknowledging the blade ...