I have recently installed Ubuntu Server (12.04.3) on a MacMini1.1...
The MacMini already had OSX (Leopard) on it and I wanted to keep it, so after much research, I used the gpart and fdisk within an "Ubuntu-Desktop i386 LiveCD"-on-a-usb-stick to shrink the OSX partition and then used an installation usb-stick-Ubuntu-Server-i386 in a similar manner to format the left-over partition and install the Ubuntu Server on it.
Everything went fine so far. Scary yet flawless process :)
Before doing all that - I installed rEFIt. I saw it on oh so many internet-guides, and remembered it from back in the day before I was an IT Manager & Tech... So I was sure it'll be THE thing to help me out.
And indeed it was great, only I missed one very important detail: On rEFIt's main webpage they clearly state: "As you may have noticed, rEFIt is no longer actively maintained. Please check out rEFInd, a fork that is maintaned and under active development."
So now all of a sudden I notice this strange phenomenon: My Ubuntu Server OS only boots up properly while I have a screen attached to the Machine(MacMini). The keyboard & mouse don't seem to be needed, but if I reboot without a screen being connected, it just gets stuck along the way and I can't access it via putty from my not-so-remote windows machine. If I then connect a screen to the MacMini, I see it got stuck along the way and there's no options to be chosen. Currently, my only option seems to be rebooting with a connected screen, then unplugging it and connecting it back to my windows-pc, where I use putty for an ssh connection over the LAN.
I decided to check rEFIt's website for troubleshooting options, when I suddenly noticed the comment about rEFInd and instantly face-palmed.
I saw that the maintainer of rEFInd is here in the forums (am I right in my realization that it's Rod Smith? So I thought after explaining the situation and how delicate it is for my work - I'd ask this supposedly simple question: I've read through the installation guide in the rEFInd site and I still don't understand how I can replace my current rEFIt with the new rEFInd without having to format anything, nor erase anything, nor delete, nor risk anything in my current system and/or files. Can you please help me?