Seemingly Random Components on DL380 G5 No Longer Work After Applying Updates

Firmware is not the problem here. HP firmware rarely bricks a server; especially that model. Your issue here is the cocktail of drivers loaded on the system.

I'd recommend using the HP Service Pack for ProLiant DVD (and the Smart Update Manager) to install system drivers, or just cherry-pick and download components directly from the support site for your OS...

Also, look through and uninstall any suspect network drivers.

I've had this situation once on a Windows 2003 server. I removed all installed HP drivers by hand, then applied the proper updates from the HP Update Manager.

This may be a long shot, but ensure the "Plug and Play" service is started on the server. If it's not, from what I've read it could cause odd issues like you're experiencing.

Otherwise, the firmware probably trashed the drivers on the server. You can attempt to uninstall/reinstall using the server DVD media (use the "Have Disk..." option) or do a repair install which will reset everything.