I have a couple older HP servers I acquired prior to understanding free firmware vs non-free. In the Debian world, when there are non-free network drivers, this can be an issue, as the non-free drivers are not included with the standard distribution downloads. Case in point, the bnx2 firmware. There are a ways to build your own distribution, but Debian, via an out of the way location, does provide an installable image: Unofficial non-free images including firmware packages
When trying out Debian Testing, here is the Debian Testing Installer page.