How to Update the BIOS in a PowerEdge 2900

I purchased a surplus PowerEdge 2900 from EBay a couple of years ago.  It is running Windows Server 2008 R2.  When I open the Open Manage Server Administrator (OSA), it shows "unknown" for the server type in upper left (whereas my other PE 2900 shows "PowerEdge 2900") and it shows BIOS version "unknown" with date 01/01/2000 (whereas my other PE 2900 shows "2.6.1" with date 04/20/2009).

My question is, what is the procedure to update the BIOS in the erroneous system?