Rebooting a headless Mac Mini

Older Mac Minis don't like running headless (without a monitor)

Here's one solution involving some cunning use of a display adaptor and a 100 Ohm resistor.

You don't need a DVI to VGA adapter. Just plug the resistor between C2 and C5 holes on the DVI. (Any of C1, C2 or C3 should work, but I tried C2 and C5 first and it worked for me so I stopped right there.)

The resistor should be about 80 Ohm, but the closest I had was 150 Ohm resistors and that worked fine. 200 or even higher probably works too.

I was able to fix headless boot on Mac Mini 2,1 (mid-2007) by putting 80 Ohms directly between DVI port pins C2 and 15 (GND). Also tested the DVI port signal and it seems no harm was done ;)

Squeezing the resistor leg to pin C5 did not make a reliable electrical connection in my case.

My headless boot problem strangely started after switching from OS X to Ubuntu.