I see the lateest firmware for the 5448 is 4.0.1.0, A01

http://support.dell.com/support/downloads/driverslist.aspx?c=us&cs=04&l=en&s=bsd&SystemID=PWC_5548&os=WNET&osl=en&servicetag=&catid=-1&impid=-1&deviceid=21903&libid=31&typeid=-1&dateid=-1&formatid=-1&source=-1&releaseid=R304771&formatcnt=2&vercnt=1

My current firmware is:
Software Version 2.0.0.43  
Boot Version 2.0.0.0  
Hardware Version 00.00.02

When I try to upload the new firmware via the Browser GUI, I get an error that says:
Status: Copy Failed  
Bytes transferred: 0  
Error message: Copy: Illegal software format

Does anybody have any ideas before I call Dell Tech support?

Thanks