Well, we all know how important firmware upgrades are and it is done using our LCM framework. In case of single node clusters, we do have to do our firmware upgrades manually as LCM framework does not work on them. 

Here let’s take an example of doing BMC upgrades manually. It is always suggested to do BMC upgrades if any before the BIOS upgrades. 

I am attaching a link to a document below that describes the steps to do BMC upgrades manually. 

https://portal.nutanix.com/#/page/kbs/details?targetId=kA032000000988sCAA

Hope the document is useful information.