I thought these might come in handy for poor i386 users:
The ISOs itself (both El Torito and Live-HD/CF boot) as well as the included 1440 KiB Floppy images have been adjusted to automatically boot from serial console. To accomodate broken BIOSes (like the one from my VIA C7 server, or the Soekris COMBIOS), the bootloader does not wait for input, but instead directly boots into the kernel. This prevents you from using “boot -c”, but you can patch boot.cfg in the top directory of the ISO or floppy to achieve that.
Users of the sparc architecture just setenv input-device ttya and setenv output-device ttya instead; OpenBOOT can handle a serial console just fine out of the box and provides the speed as well.