iDRAC7 + OME + CentOS

I am trying to use OME (1.3) to manage a group of five CentOS-based PowerEdge servers (1 x R320, 4 x R620) each of which has an iDRAC7 Enterprise controller. The iDrac firmware revision on the R320 is 1.30.30, two of the R620s are at 1.56.55, the other two 620s are at 1.20.20.

The problem I have is that after discovery an inventory (using WS-MAN) OME sees the operating system on the 320 as Centos, and N/A on the R620s. The consequence of this is that OME decides to upgrade firmware on the servers using WIN32 packages which does not work.

I see the following on the actual iDRAC consoles. On the iDRAC associated with the 320 (1.30.30) I see the operating system as CentOS, on the consoles with the 1.20.20 firmware I also see the OS as Centos, but on the consoles with 1.56.55 firmware the operating system fields are blank.

I am trying to debug/understand the following issues:

How does the iDRAC determine the OS, and do I have any control over the process given that OME would prefer to see the OS as RHEL

The OME folks recommended upgrading to the latest iDRAC firmware (1.56.55); I would liek to get confirmation on this.

Any help would be much appreciated.

Thanks. Peter