Just a quick note: the HP z620 supports booting without a graphics card, but it’s hidden. Steps to enable:
- enter the BIOS -> replicated setup -> save to a FAT32 formatted USB
- boot some computer, attach the USB, edit the file: there’s a “Headless Mode” section with two options, “Enabled” and “Disabled” and a silly star simulating a GUI widget. Move the star from Disabled to Enabled
- Save with Windows line ending (CR LR)
- enter the BIOS -> replicated setup -> restore
- Save settings
You’re done.
George's Techblog 