Funny that you post this, I just picked up a Javastation-1 (aka Mr. Coffee) and have been trying to get it working... It's a little different hardware-wise than your Krups but maybe some of my experience will be useful. Mine has the newer 3.x OpenBoot/OFW so it should boot in a similar way to your Krups.
I replaced the NVRAM, but I couldn't break into OpenBoot to reprogram it so I ended up doing that on a different machine. I later found out that a Manufacturing Test jumper on the board will give you a 6 second window to break into the prompt.
I got NetBSD (6.1.5) booting on it which was not terribly difficult, you just need a DHCP server that can set the "next server", "boot file" and "root path" dhcp options, then a TFTP server with the javastation-specific "bootjs.net" netbsd bootloader on it (the "boot file" param), and then an NFS server (path on the "next server" in the "root path" param) with the NetBSD binary sets extracted and the appropriate kernel - there are specific kernels for Mr Coffee and Krups Javastations included.
The console is kinda messed up looking and I can't get X working, but it does boot!