MP 1,1-5,1 Mac Pro 5,1 (flashed 4,1) Headless Setup Question

[macman808]

I am upgrading from Monterey to Ventura on two Mac Pro 5,1s (flashed 4,1) which I have had running in a headless configuration for several years now. I can't get them to boot without a display, and keyboard/mouse connected. If I do not have a display connected it goes into recovery mode. If I do not have mouse and keyboard connected it goes to support.apple.com\macsetup prompt. Anyone have any ideas on how run with no display, mouse and keyboard?

 

[JedNZ]

Have you tried using a headless HDMI dongle which would force video acceleration?

 

[macman808]

Have you tried using a headless HDMI dongle which would force video acceleration?

I have not. I will get one and try it out. Thank you!!!