PE6650 - booting issue after firmware/bios update

[Tom Brown]

Hi

A number of my 6650's was giving firmware out of date errors since 
installing OMSA so i figured it was about time i updated them. The first 
one i did went fine and using the following ISO

http://ftp.us.dell.com/sysman/4.5_OM_SUU_A00.iso

The second one i did this weekend again seemed to update fine but did 
not come back on the reboot. At the console it is giving me.

No valid boot device (or something similar i should go and check)

I have booted using the OMSA live CD and everything appears OK including 
the firmware errors what were showing before. I have googled this a bit 
and it seems that perhaps this is some form of hardware issue as its not 
saying 'Operating System Not Found'

In the bios the PERC is set as the HDD and the SCSI controller is also 
found and enabled.

Does anyone have any ideas as to this one?

thanks