There are multiple ways to upgrade DELL Server firmware. However, frankly speaking, DELL server upgrade is not easy enough comparing with HP or Cisco Servers. HP provides SPP and Cisco provide HUU/firmware pack for UCS system, which consolidate and align all the driver/firmware to be at the same level to make the upgrade workflow easier. In general, the recommended DELL upgrade workflow and available methods are detailed in the below document.
http://en.community.dell.com/techcenter/extras/m/white_papers/20408841/download.aspx
In this post, we will utilize the DELL Repository Manager to upgrade the Dell Servers.