We are using Nutanix 3000 (SuperMicro Server) and while upgrading the Firmware for bmc i noticed that it didn't take affect. In our case i had to ssh into the VM host and Shut it down using command line. To get bmc working , we needed to pull the host out of the chassis and then put it back in . IPMI worked fine after that and did show the upgraded firmware version. Hope this helps.